担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Kisspeptin neurons, i.e. KNDy neurons, in the arcuate nucleus (ARC) coexpress neurokinin B and dynorphin and regulate gonadotropin-releasing hormone/luteinizing hormone (LH) pulses. Because it remains unclear whether these neurons are associated with reproductive dysfunction in diabetic females, we examined the expression of KNDy neurons detected by histochemistry in streptozotocin (STZ)-induced diabetic female rats 8 weeks after STZ injection. We also evaluated relevant metabolic parameters - glucose, 3-hydroxybutyrate, and non-esterified fatty acids - as indicators of diabetes progression. Severe diabetes with hyperglycemia and severe ketosis suppressed the mRNA expression of KNDy neurons, resulting in low plasma LH levels and persistent diestrus. In moderate diabetes with hyperglycemia and moderate ketosis, kisspeptin-immunoreactive cells and plasma LH levels were decreased, while the mRNA expression of KNDy neurons remained unchanged. Mild diabetes with hyperglycemia and slight ketosis did not affect KNDy neurons and plasma LH levels. The number of KNDy cells was strongly and negatively correlated with plasma 3-hydroxybutyrate levels. The vaginal smear analysis showed unclear proestrus in diabetic rats 3-5 days after STZ injection, and the mRNA expression of kisspeptin in the ARC was decreased 2 weeks after STZ injection in severely diabetic rats. Kisspeptin neurons in the anteroventral periventricular nucleus (AVPV), which induce an LH surge, were unaffected at 2 and 8 weeks after STZ injection regardless of the diabetes severity. These results suggest that diabetes mellitus progression in females may negatively affect ARC kisspeptin neurons but not AVPV kisspeptin neurons, implicating a potential role of ARC kisspeptin neurons in menstrual disorder and infertility.

DOI： 10.1530/JOE-21-0169

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Metabolic stress resulting from either lack or excess of nutrients often causes infertility in both sexes. Kisspeptin-neurokinin B-dynorphin A (KNDy) neurons in the arcuate nucleus (ARC) has been suggested to be a key players in reproduction via direct stimulation of the pulsatile gonadotropin-releasing hormone (GnRH) and subsequent gonadotropin release in mammalian species. In this study, we investigated the effect of high-fat diet (HFD) on hypothalamic KNDy gene expression to examine the pathogenic mechanism underlying obesity-induced infertility in male and female rats. Male and female rats at 7 weeks of age were fed with either a standard or HFD for 4 months. In the male rats, the HFD caused a significant suppression of ARC Kiss1 and Pdyn gene expressions, but did not affect the plasma luteinizing hormone (LH) levels and sizes of the morphology of the testis and epididymis. In the female rats, 58% of the HFD-fed female rats exhibited irregular estrous cycles, whereas the remaining rats showed regular cycles. Two of the 10 rats that showed HFD-induced irregular estrous cycles showed profound suppression of LH pulse frequency and the number of ARC Kiss1-expressing cells, whereas the other females showed normal LH pulses and ARC Kiss1 expression. Our finding shows that suppression of ARC Kiss1 expression might be the initial pathological change of hypogonadotropic hypogonadism in HFD-fed male rats, while the obese-related infertility in the female rats may be mainly induced by KNDy-independent pathways. Taken together, ARC kisspeptin neurons in male rats may be susceptible to HFD-induced obesity compared with those in female rats.

DOI： 10.1016/j.peptides.2021.170546

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担当区分：筆頭著者,　責任著者   記述言語：日本語   出版者・発行元：日本医科大学医学会  

視床下部のkisspeptinは生殖機能の制御に非常に重要な神経ペプチドであり、kisspeptinニューロンの機能不全は、生殖機能の抑制につながる。視床下部のkisspeptinニューロンは体内の様々な情報を感知し、それらを統合して下位の性腺刺激ホルモン放出ホルモン(GnRH)ニューロンを制御することにより生殖機能を制御していると考えられる。アンドロゲンとkisspeptinニューロン、加齢とkisspeptinニューロン、プロラクチンとkisspeptinニューロンについて述べた。

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その他リンク： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2020&ichushi_jid=J04260&link_issn=&doc_id=20200520320009&doc_link_id=10.1272%2Fmanms.16.110&url=https%3A%2F%2Fdoi.org%2F10.1272%2Fmanms.16.110&type=J-STAGE&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00007_3.gif

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Hypothalamic kisspeptin neurons stimulate gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) release. Kisspeptin neurons in the anteroventral periventricular nucleus (AVPV) of rats induce an LH surge for ovulation, and those in the arcuate nucleus (ARC) regulate pulsatile LH secretion for follicle development and spermatogenesis. Dysfunction of kisspeptin neurons thus reduces the reproductive function. This review focuses on the effect of androgen or aging on kisspeptin expression in rats. Although androgen directly suppresses ARC kisspeptin neurons in female rats, the AVPV kisspeptin neurons are hardly affected. In rats, plasma LH concentrations decrease in both sexes with aging, and ARC kisspeptin expression also decreases in old rats compared with young rats. In addition, kisspeptin neurons may be associated with hyperprolactinemia in old female rats because they are known to release prolactin through hypothalamic tuberoinfundibular dopaminergic (TIDA) neurons. Hypothalamic kisspeptin neurons are thus the main regulator to secrete LH, and inhibition of kisspeptin expression leads to various kinds of reproductive dysfunction.

DOI： 10.1267/ahc.19013

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s00418-018-01767-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier Ireland Ltd  

Zucker fatty (ZF) rats are considered to be an obese model due to leptin receptor abnormality and such rats show infertility. Pulsatile gonadotropin-releasing hormone/luteinizing hormone (LH) secretion, which is important for follicular development in females, is considered to be controlled by KNDy neurons coexpressing kisspeptin, neurokinin B (NKB), and dynorphin A (DynA), encoded by Kiss1, Tac3, and Pdyn, respectively, in the hypothalamic arcuate nucleus (ARC). The purpose of this study is to examine the expression of KNDy neurons in female ZF rats by histochemical approach because pulsatile LH secretion is suppressed. Zucker lean (ZL) rats served as a control group. Animals were ovariectomized and subcutaneously implanted with a silicon tube containing estradiol to produce plasma level of estradiol during diestrus. Plasma LH levels decreased in ZF rats compared with ZL rats. The expressions of each mRNA (Kiss1, Tac3, and Pdyn) and each peptide (kisspeptin, NKB, and DynA) in the ARC significantly decreased in ZF rats compared with ZL rats. However, the number of Kiss1 neurons in the anterior ventral periventricular nucleus did not significantly differ between the two groups. These results suggest that dysfunction of leptin signaling negatively affects KNDy neurons in the ARC, resulting in reproductive dysfunction caused by suppression of the LH pulse.

DOI： 10.1016/j.neulet.2017.12.002

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：OXFORD UNIV PRESS INC  

Kisspeptin (KISS1; encoded by Kiss1) neurons in the arcuate nucleus (ARC) coexpress tachykinin 3 (TAC3; also known as neurokinin B) and dynorphin A (PDYN). Accordingly, they are termed KNDy neurons and considered to be crucial in generating pulsatile release of gonadotropin-releasing hormone. Accumulating evidence suggests that Kiss1 and Tac3 are negatively regulated by estrogen. However, it has not been fully determined whether and how estrogen modulates Pdyn and PDYN. Here, we examined the expression of Pdyn mRNA and PDYN by in situ hybridization and immunohistochemistry, respectively, in the ARC of female rats after ovariectomy (OVX) and OVX plus low-or high-dose beta-estradiol (E-2) replacement. We also investigated the effect of E-2 on expression of Kiss1, KISS1, Tac3, and TAC3. Furthermore, colocalization of PDYN and estrogen receptor alpha (ESR1) was determined. Subsequently, we found that low-dose E-2 treatment had no effect on Pdyn mRNA-expressing cells, but increased PDYN-immunoreactive (ir) cell numbers. In contrast, high-dose E-2 treatment resulted in prominent reductions in both Pdyn mRNA-expressing and PDYN-ir cell numbers. Changes induced by low or high doses of E-2 were similarly observed in the expression of Kiss1, KISS1, Tac3, and TAC3. The majority of PDYN-ir neurons coexpressed ESR1 in all groups. Our results indicate that E-2 regulates the expression of PDYN, as well as KISS1 and TAC3, with regulation by E-2 differing according to its levels.
Summary Sentence
Estrogen regulates dynorphin expression in the arcuate nucleus of female rats with low-dose estrogen suppressing dynorphin release and high-dose estrogen inhibiting dynorphin mRNA expression.

DOI： 10.1093/biolre/iox131

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BIOSCIENTIFICA LTD  

Hyperandrogenic women have various grades of ovulatory dysfunction, which lead to infertility. The purpose of this study was to determine whether chronic exposure to androgen affects the expression of kisspeptin (ovulation and follicle development regulator) or release of luteinizing hormone (LH) in female rats. Weaned females were subcutaneously implanted with 90-day continuous-release pellets of 5 alpha-dihydrotestosterone (DHT) and studied after 10 weeks of age. Number of Kiss1-expressing cells in both the anteroventral periventricular nucleus (AVPV) and arcuate nucleus (ARC) was significantly decreased in ovary-intact DHT rats. Further, an estradiol-induced LH surge was not detected in DHT rats, even though significant differences were not observed between DHT and non-DHT rats with regard to number of AVPV Kiss1-expressing cells or gonadotrophin-releasing hormone (GnRH)-immunoreactive (ir) cells in the presence of high estradiol. Kiss1-expressing and neurokinin B-ir cells were significantly decreased in the ARC of ovariectomized (OVX) DHT rats compared with OVX non-DHT rats; pulsatile LH secretion was also suppressed in these animals. Central injection of kisspeptin-10 or intravenous injection of a GnRH agonist did not affect the LH release in DHT rats. Notably, ARC Kiss1-expressing cells expressed androgen receptors (ARs) in female rats, whereas only a few Kiss1-expressing cells expressed ARs in the AVPV. Collectively, our results suggest excessive androgen suppresses LH surge and pulsatile LH secretion by inhibiting kisspeptin expression in the ARC and disruption at the pituitary level, whereas AVPV kisspeptin neurons appear to be directly unaffected by androgen. Hence, hyperandrogenemia may adversely affect ARC kisspeptin neurons, resulting in anovulation and menstrual irregularities.

DOI： 10.1530/JOE-16-0568

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCIENCE INC  

Pulsatile secretion of gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) decreases during aging. Kisspeptin (encoded by Kiss1) neurons in the arcuate nucleus coexpress neurokinin B (Tac3) and dynorphin (Pdyn) and are critical for regulating the GnRH/LH pulse. We therefore examined kisspeptin neurons by histochemistry and pulsatile LH release in rats aged 2-3 (Young), 12-13 (YoungMiddle), 19-22 (Late-Middle), and 24-26 (Old) months. Total LH concentrations, sampled for 3 hours, decreased in both sexes with aging. In females, numbers of Tac3 and Pdyn neurons were significantly reduced in all aging rats, and numbers of Kiss1 neurons were significantly reduced in Late-Middle and Old rats. In males, numbers of all 3 neuron-types were significantly decreased in all aging rats. GnRH agonist induced LH release in all animals; however, the increased LH concentration in all aging rats was less than that in Young rats. These results suggest that expression of each gene in kisspeptin neurons may be controlled individually during aging, and that reduction of their expression or change in pituitary responsiveness may cause attenuated pulsatile LH secretion. (C) 2016 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.neurobiolaging.2016.10.018

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER IRELAND LTD  

KNDy neurons are named for their co-expression of three neuropeptides, kisspeptin, neurokinin B (NKB) and dynorphin A (DynA). These cells, located in the hypothalamic arcuate nucleus (ARC), are associated with generation of gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) pulses to control follicular growth and steroidogenesis. However, subcellular sorting mechanisms for secretory vesicles containing these neuropeptides have not been elucidated. In this study, we analyzed the localization pattern of kisspeptin, NKB and DynA in the ARC of the ovariectomized rat immediately treated with estrogen using immunoelectron microscopy. First, we identified neuropeptides by dual-labeled fluorescence immunohistochemistry, with results indicating all three neuropeptides co-express within individual ARC cells in female rats. Next, we investigated the subcellular localization pattern of kisspeptin, NKB, and/or DynA using post-embedding double immunoelectron microscopy, indicating that each type of neuropeptide is contained within separate and individual neurosecretory vesicles. This suggests sorting and packaging of kisspeptin, NKB and DynA is differentially regulated within KNDy neurons. Our findings facilitate understanding of regulatory mechanisms underlying kisspeptin secretion in KNDy neurons, and generation of GnRH/LH pulses induced by kisspeptin in the ARC. (C) 2015 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.neulet.2015.12.008

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：JAPAN SOC HISTOCHEMISTRY & CYTOCHEMISTRY  

Kisspeptin neurons in the arcuate nucleus (ARC) regulate prolactin secretion, and are in physical contact with tuberoinfundibular dopaminergic (TIDA) neurons, which inhibit prolactin secretion. Prolactin levels in the blood are increased with advancing age in rats; therefore, we investigated the interactions with TIDA neurons and kisspeptin neurons in aged female rats (24 months of age), relative to those of young adult female rats (9-10 weeks of age). Plasma prolactin levels in the aged rats were significantly higher than those of young adult rats. Tyrosine hydroxylase (TH)-immunoreactive (ir) cell bodies and kisspeptin-ir nerve fibers were found in the dorsomedial ARC of both groups. The number of TH-ir cell bodies in the dorsomedial ARC did not differ significantly between groups. Additionally, no significant differences in the number of TH-ir cells in contact with kisspeptin-ir fibers was observed between groups. However, the number of kisspeptin-ir or Kiss1 mRNA-expressing cells in the ARC was significantly reduced in the aged rats compared with that of the young rats. These results suggest that the contacts between TIDA neurons and kisspeptin neurons are maintained after reproductive senescence, while production of kisspeptin in the ARC decreases significantly during aging.

DOI： 10.1267/ahc.16027

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER IRELAND LTD  

Disorders caused by the malfunction of the serotonergic system in the central nervous system show sex-specific prevalence. Many studies have reported a relationship between sex steroid hormones and the brain serotonergic system; however, the interaction between sex steroid hormones and the number of brain neurons expressing serotonin has not yet been elucidated. In the present study, we determined whether sex steroid hormones altered the number of serotonergic neurons in the dorsal raphe nucleus (DR) of adult rat brains. Animals were divided into five groups: ovariectomized (OVX), OVX+ low estradiol (E2), OVX+ high E2, castrated males, and intact males. Antibodies against 5-hydroxytryptamine (5-HT, serotonin) and tryptophan hydroxylase (Tph), an enzyme for 5-HT synthesis, were used as markers of 5-HT neurons, and the number of 5-HT-immunoreactive (ir) or Tph-ir cells was counted. We detected no significant differences in the number of 5-HT-ir or Tph-ir cells in the DR among the five groups. By contrast, the intensity of 5-HT-ir showed significant sex differences in specific subregions of the DR independent of sex steroid levels, suggesting that the manipulation of sex steroid hormones after maturation does not affect the number and intensive immunostaining of serotonergic neurons in rat brain. Our results suggest that, the sexual dimorphism observed in the serotonergic system is due to factors such as 5-HT synthesis, transportation, and degradation but not to the number of serotonergic neurons. (C) 2015 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.neulet.2015.03.060

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：JAPAN SOC HISTOCHEMISTRY & CYTOCHEMISTRY  

Glucocorticoid receptor (GR) is a ligand-activated nuclear receptor which is widely distributed in the brain. Many types of neurons and glial cells are known to express GR, but the expression of GR in ependymal cells has yet to be identified. The present study therefore was undertaken to determine whether ependymal cells express GR and coactivators of GR, such as steroid receptor coactivator 1 (SRC-1) and p300. GR immunoreactivity was found in cells immunopositive to vimentin, a marker of ependymal cells, around the third ventricle (3V), the lateral ventricle (LV), the cerebral aqueduct and the fourth ventricle (4V), whereas the expression of GR in vimentin-immunoreactive (ir) cells was significantly reduced by adrenalectomy (ADX) in male rats. Vimentin-ir cells also expressed both SRC-1 and p300 at around 3V, LV, the cerebral aqueduct and 4V. ADX had no effect on the expression of SRC-1 or p300 in vimentin-ir cells. These results suggest that glucocorticoid may exert effects on ependymal cells through binding to GR followed by association with SRC-1 and p300 to maintain brain environment under stressful conditions.

DOI： 10.1267/ahc.14021

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER JAPAN KK  

Kisspeptins, encoded by Kiss1 gene, play pivotal roles in the regulation of reproduction. Recently, several studies reported a sex difference in Kiss1 expression in the arcuate nucleus (ARC) during the neonatal period. In this study, we investigated the effect of gonadal steroid manipulation on the sex difference in Kiss1 expression in ARC of rats. At neonatal and prepubertal stages, females had a greater number of Kiss1 neurons than the males. Gonadectomy at those stages resulted in significant increases in the Kiss1 neuron number and the sex differences disappeared. We also confirmed the expression of estrogen receptor alpha in kisspeptin neurons in neonates. Altogether, our results indicate that ARC Kiss1 expression is negatively regulated by gonadal steroids from early postnatal stages, and that the sex difference in ARC Kiss1 expression is attributed to the difference in circulating gonadal steroid levels. We also found that neonatal estrogenization inhibits Kiss1 expression and impairs negative feedback system.

DOI： 10.1007/s12576-012-0222-y

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

Follicular development and ovulation are strongly suppressed during lactation in mammals via a profound suppression of gonadotrophin secretion. The present study aimed to examine the role of oestrogen feedback action in suppressing luteinising hormone (LH) secretion and hypothalamic kisspeptin expression during the latter half of lactation. Plasma LH concentrations kept at low levels throughout the lactating period in intact and oestrogen-replaced ovariectomised (OVX) lactating rats, whereas plasma LH concentrations gradually elevated from day 10 postpartum in lactating OVX rats. OVX lactating rats showed frequent LH pulses at late lactation, although the LH pulses were significantly inhibited by an oestrogen replacement, which is much less effective on LH release in nonlactating rats. Oestrogen replacement in lactating OVX rats significantly reduced the number of Kiss1 mRNA-expressing cells in the arcuate nucleus (ARC) at late lactation, although the same oestrogen treatment did not affect the number of Kiss1-expressing cells in nonlactating controls. Exogenous kisspeptin challenge (0.2 nmol) into the third cerebroventricle significantly increased LH secretion in lactating OVX, lactating OVX + subcutaneous 17 beta-oestradiol and intact lactating rats at day 16 postpartum. These results suggest that LH pulse suppression during late lactation could be a result of the enhanced oestrogen-dependent suppression of ARC kisspeptin expression.

DOI： 10.1111/j.1365-2826.2012.02330.x

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記述言語：英語   出版者・発行元：MEDICAL ASSOC NIPPON MEDICAL SCH  

DOI： 10.1272/jnms.79.168

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SOCIETY REPRODUCTION & DEVELOPMENT-SRD  

Ketosis is found in various pathophysiological conditions, including diabetes and starvation, that are accompanied by suppression of gonadal activity. The aim of the present study was to determine the role of ketone body in the brain in regulating pulsatile luteinizing hormone (LH) secretion in female rats. Injection of 3-hydroxybutyrate (3HB), a ketone body, into the fourth cerebroventricle (4V) induced suppression of pulsatile LH secretion in a dose-dependent manner in ovariectomized (OVX) rats with an estradiol (E2) implant producing diestrus plasma E2 levels. Plasma glucose and corticosterone levels increased immediately after the 4V 3HB injection, suggesting that the treatment caused a hunger response. The 3HB-induced suppression of LH pulses might be mediated by noradrenergic inputs to the hypothalamic paraventricular nucleus (PVN) because a local injection of alpha-methyl-p-tyrosine, a catecholamine synthesis inhibitor, into the PVN blocked 3HB-induced suppression of LH pulses and PVN noradrenaline release was increased by 4V 3HB injection in E2-primed OVX rats. These results suggest that ketone body sensed by a central energy sensor in the hindbrain may suppress gonadotropin release via noradrenergic inputs to the PVN under ketosis.

DOI： 10.1262/jrd.11-001S

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER TOKYO  

Uncontrolled type 1 diabetes leads to hyperphagia and severe ketosis. This study was conducted to test the hypothesis that ketone bodies act on the hindbrain as a starvation signal to induce diabetic hyperphagia. Injection of an inhibitor of monocarboxylate transporter 1, a ketone body transporter, into the fourth ventricle normalized the increase in food intake in streptozotocin (STZ)-induced diabetic rats. Blockade of catecholamine synthesis in the hypothalamic paraventricular nucleus (PVN) also restored food intake to normal levels in diabetic animals. On the other hand, hindbrain injection of the ketone body induced feeding, hyperglycemia, and fatty acid mobilization via increased sympathetic activity and also norepinephrine release in the PVN. This result provides evidence that hyperphagia in STZ-induced type 1 diabetes is signaled by a ketone body sensed in the hindbrain, and mediated by noradrenergic inputs to the PVN.

DOI： 10.1007/s12576-010-0127-6

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SOC STUDY REPRODUCTION  

The brain mechanism regulating gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) release is sexually differentiated in rodents. Kisspeptin neurons in the anteroventral periventricular nucleus (AVPV) have been suggested to be sexually dimorphic and involved in the GnRH/LH surge generation. The present study aimed to determine the significance of neonatal testicular androgen to defeminize AVPV kisspeptin expression and the GnRH/LH surge-generating system. To this end, we tested whether neonatal castration feminizes AVPV kisspeptin neurons and the LH surge-generating system in male rats and whether neonatal estradiol benzoate (EB) treatment suppresses the kisspeptin expression and the LH surge in female rats. Immunohistochemistry, in situ hybridization, and quantitative real-time RT-PCR were performed to investigate kisspeptin and Kiss1 mRNA expressions. Male rats were castrated immediately after birth, and females were treated with EB on postnatal Day 5. Neonatal castration caused an increase in AVPV kisspeptin expression at peptide and mRNA levels in the genetically male rats, and the animals showed surge-like LH release in the presence of the preovulatory level of estradiol (E2) at adulthood. On the other hand, neonatal EB treatment decreased the number of AVPV kisspeptin neurons and caused an absence of E2-induced LH surge in female rats. Semiquantitative RT-PCR analysis showed that neonatal steroidal manipulation affects Kiss1 expression but does not significantly affect gene expressions of neuropeptides (neurotensin and galanin) and enzymes or transporter for neurotransmitters (gamma-aminobutyric acid, glutamate, and dopamine) in the AVPV, suggesting that the manipulation specifically affects Kiss1 expressions. Taken together, our present results provide physiological evidence that neonatal testicular androgen causes the reduction of AVPV kisspeptin expression and failure of LH surge in genetically male rats. Thus, it is plausible that perinatal testicular androgen causes defeminization of the AVPV kisspeptin system, resulting in the loss of the surge system in male rats.

DOI： 10.1095/biolreprod.109.078311

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SOCIETY REPRODUCTION & DEVELOPMENT-SRD  

Ketone bodies are considered to act as a signal to suppress gonadotropin release during negative energy balance. The present study examined the effect of 48-h fasting on the mRNA expressions of monocarboxylate transporter 1 (MCT1) and MCT2, which are involved in ketone body transport, in several brain regions. Quantitative real-time RT-PCR analysis showed that the MCT2 mRNA levels were significantly increased by 48-h fasting in the area postrema-solitary tract nucleus (AP-NTS) region but not the arcuate nucleus-ventromedial hypothalamic nucleus (ARC-VMH) and central gray-supragenual nucleus around the 4th ventricle (CG-SGe) regions. Fasting did not significantly affect MCTI mRNA expression in any of the brain areas examined. Luteinizing hormone (LH) pulse frequency significantly decreased and plasma concentrations of beta-hydroxybutyric acid, a ketone body, significantly increased after 48-h fasting. The present results suggest that increased uptake of ketone bodies via MCT2 in the AP-NTS region is likely involved in the mechanism of fasting-induced suppression of LH secretion in rats.

DOI： 10.1262/jrd.20214

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ENDOCRINE SOC  

The present study aims to clarify the role of fatty acids in regulating pulsatile LH secretion in rats. To produce an acute central lipoprivic condition, mercaptoacetate (MA), an inhibitor of fatty acids oxidation, was administered into the fourth cerebroventricle (4V) in ad libitum fed ovariectomized (OVX) rats (0.4, 2, and 10 mu mol/rat) with or without an estradiol (E2) implant producing diestrus plasma E2 levels. Pulsatile LH secretion was suppressed by 4V MA administration in a dose-dependent manner in both OVX and OVX plus E2 rats. Mean LH levels and LH pulse frequency and amplitude were significantly reduced by the highest dose of MA in OVX rats, and by the middle and highest dose of MA in E2-treated rats, suggesting that estrogen enhanced LH suppression. Blood glucose levels increased immediately after the highest dose of MA in both groups. Fourth ventricular injection of trimetazidine (2 and 3 mu mol/rat), another inhibitor of fatty acids oxidation, also inhibited pulsatile LH release, resulting in significant and dose-dependent suppression of LH pulse frequency and an increase in blood glucose levels in OVX plus E2 rats. In contrast, peripheral injection of the highest 4V dose of MA (10 mu mol/rat) did not alter LH release or blood glucose levels. Microdialysis of the hypothalamic paraventricular nucleus (PVN) revealed that norepinephrine release in the region was increased by 4V MA administration. Preinjection of alpha-methyl-p-tyrosine, a catecholamine synthesis inhibitor, into the PVN completely blocked the lipoprivic inhibition of LH and the counter-regulatory increase in blood glucose levels in OVX plus E2 rats. Together, these studies indicate that fatty acid availability may be sensed by a central detector, located in the lower brainstem to maintain reproduction, and that noradrenergic inputs to the PVN mediate this lipoprivic-induced suppression of LH release.

DOI： 10.1210/en.2008-0016

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SOCIETY REPRODUCTION & DEVELOPMENT-SRD  

Acute central lipoprivation suppresses pulsatile luteinizing hormone (LH) release and increases blood glucose levels through noradrenergic input to the hypothalamic paraventricular nucleus (PVN) in female rats. The present study was conducted to identify adrenergic receptor subtypes involved in central lipoprivation-induced suppression of pulsatile LH secretion and increases in plasma glucose levels in female rats. Acute hindbrain lipoprivation was produced by injection into the fourth cerebroventricle (4V) of 2-mercaptoacetate (MA), an inhibitor of fatty acid oxidation, in estradiol-implanted ovariectomized rats. Two min before MA injection, alpha 1-, alpha 2- or beta-adrenergic receptor antagonist was injected into the PVN. Injection of MA into the 4V suppresses pulsatile LH release in PVN vehicle-treated rats, whereas pretreatment of animals with injection of alpha 1- or alpha 2-adrenergic antagonist into the PVN blocked the effect of the 4V MA injection on LH pulses. beta-Adrenergic antagonist did not affect MA-induced suppression of LH pulses. The counter-regulatory increase in plasma glucose levels after 4V MA injection was also partially blocked by pretreatment with alpha 1- and alpha 2-adrenergic receptor antagonists. These results suggest that alpha 1- and alpha 2-adrenergic receptors in the PVN mediate hindbrain lipoprivation-induced suppression of LH release and counter-regulatory increases in plasma glucose levels in female rats.

DOI： 10.1262/jrd.20024

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PubMed

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BLACKWELL PUBLISHING  

Galanin-like peptide (GALP), a ligand for three types of galanin receptor, is reported to have a role in regulating luteinising hormone (LH) release in male rodents and primates, but its role in LH release in female rodents remains controversial. The present study was conducted to test whether GALP has a stimulatory role in regulating LH secretion in female rats. The effect of i.c.v. infusion of GALP (5 nmol) on pulsatile LH release was investigated in Wistar-Imamichi strain female rats, or lean and obese Zucker rats. In oestradiol-17 beta (oestradiol)-primed ovariectomised (OVX) Wistar-Imamichi female rats, i.c.v. infusion of GALP caused a gradual increase in LH release for the first 1.5 h after the infusion followed by an increased LH pulse frequency during the next 1.5 h, resulting in a significant increase in the mean LH concentrations and baseline levels of LH pulses throughout the sampling period and in the frequency of LH pulses at the last half of the period compared to vehicle-treated controls. The stimulatory effect of GALP was oestrogen-dependent because the same GALP treatment did not affect LH release in OVX rats in the absence of oestradiol. In lean Zucker rats, LH pulses were found in oestradiol-primed OVX individuals and central GALP infusion increased mean LH concentrations in the last half of the period. By contrast, few LH pulses were found in oestradiol-primed OVX obese Zucker rats reportedly with lower hypothalamic GALP expression. Central GALP infusion caused an apparent but transient increase in LH release, resulting in the significant increase in all pulse parameters of LH pulses compared to vehicle-treated controls in the first half of the sampling period. These results suggest that hypothalamic GALP is likely involved in stimulating GnRH/LH release, and that the stimulatory effect of GALP on LH release is oestrogen-dependent in female rats.

DOI： 10.1111/j.1365-2826.2008.01703.x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ENDOCRINE SOC  

Follicular development and ovulation are suppressed during lactation in various mammalian species, mainly due to the suppression of pulsatile GnRH/LH secretion. Metastin (kisspeptin-54), a KiSS-1 gene product, is an endogenous ligand for GPR54, a G-protein-coupled receptor, and suggested to play a critical role in regulating the gonadal axis. The present study therefore aims to determine whether metastin (kisspeptin-54)-GPR54 signaling in discrete brain areas is inhibited by the suckling stimulus that causes suppression of LH secretion in lactating rats. Quantitative RT-PCR revealed that the KiSS-1 mRNA level was significantly lower in the arcuate nucleus (ARC)-median eminence region in lactating ovariectomized (OVX) and estrogen-treated OVX rats than in nonlactating controls. KiSS-1 mRNA in the anteroventral periventricular nucleus was kept at a low level in both lactating and nonlactating rats despite estrogen treatment. GPR54 mRNA levels were significantly lower in lactating than nonlactating rats in the anteroventral periventricular nucleus, but the levels in lactating mothers of the preoptic area and ARC-median eminence were comparable with nonlactating controls. Although KiSS-1 mRNA-expressing cells or metastin (kisspeptin-54) immunoreactivities were densely located in the ARC of nonlactating controls, few were found in the ARC of lactating OVX animals. Various doses of metastin (kisspeptin-54) (0.02, 0.2, and 2 nmol) injected into the third ventricle caused a significant increase in LH secretion in both lactating and nonlactating OVX rats, suggesting that lactating rats are responsive to metastin ( kisspeptin-54) stimulus. Thus, the present study demonstrated that KiSS-1 mRNA/metastin ( kisspeptin-54) expression is inhibited in the ARC by the suckling stimulus, suggesting that the inhibition is most probably involved in suppressing LH secretion in lactating rats.

DOI： 10.1210/en.2006-1529

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ENDOCRINE SOC  

Ovulation is caused by a sequence of neuroendocrine events: GnRH and LH surges that are induced by positive feedback action of estrogen secreted by the mature ovarian follicles. The central mechanism of positive feedback action of estrogen on GnRH/LH secretion, however, is not fully understood yet. The present study examined whether metastin, the product of metastasis suppressor gene KiSS-1, is a central neuropeptide regulating GnRH/LH surge and then estrous cyclicity in the female rat. Metastin had a profound stimulation on LH secretion by acting on the preoptic area (POA), where most GnRH neurons projecting to the median eminence are located, because injection of metastin into the third ventricle or POA increased plasma LH concentrations in estrogen-primed ovariectomized rats. Metastin neurons were immunohistochemically found in the arcuate nucleus (ARC) to be colocalized with estrogen receptors with some fibers in the preoptic area (POA) in close apposition with GnRH neuronal cell bodies or fibers. Quantitative RT-PCR has revealed that KiSS-1 and GPR54 mRNAs were expressed in the ARC and POA, respectively. The blockade of local metastin action in the POA with a specific monoclonal antibody to rat metastin completely abolished proestrous LH surge and inhibited estrous cyclicity. Metastin-immunoreactive cell bodies in the ARC showed a marked increase and c-Fos expression in the early proestrus afternoon compared with the day of diestrus. Thus, metastin released in the POA is involved in inducing the pre-ovulatory LH surge and regulating estrous cyclicity.

DOI： 10.1210/en.2005-0195

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PubMed

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記述言語：日本語   出版者・発行元：(一社)日本内分泌学会  

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J-GLOBAL

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記述言語：日本語   出版者・発行元：(一社)日本内分泌学会  

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記述言語：日本語   出版者・発行元：(公社)日本繁殖生物学会  

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記述言語：日本語   出版者・発行元：日本組織細胞化学会  

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記述言語：日本語   出版者・発行元：日本組織細胞化学会  

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記述言語：日本語   出版者・発行元：(一社)日本内分泌学会  

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記述言語：日本語   出版者・発行元：(一社)日本生殖医学会  

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J-GLOBAL

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記述言語：日本語  

J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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記述言語：日本語  

J-GLOBAL

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記述言語：日本語   出版者・発行元：日本産科婦人科学会  

CiNii Books

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その他リンク： https://projects.repo.nii.ac.jp/?action=repository_uri&item_id=454633

J-GLOBAL

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記述言語：日本語   出版者・発行元：日本組織細胞化学会  

CiNii Books

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その他リンク： http://search.jamas.or.jp/link/ui/2015114179

記述言語：日本語   出版者・発行元：日本組織細胞化学会  

CiNii Books

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その他リンク： http://search.jamas.or.jp/link/ui/2015114181

J-GLOBAL

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記述言語：日本語   出版者・発行元：日本組織細胞化学会  

CiNii Books

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その他リンク： http://search.jamas.or.jp/link/ui/2014022074

記述言語：日本語  

J-GLOBAL

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記述言語：日本語   出版者・発行元：(一社)日本内分泌学会  

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記述言語：日本語   出版者・発行元：日本顕微鏡学会  

CiNii Books

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記述言語：日本語  

J-GLOBAL

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記述言語：日本語   出版者・発行元：日本組織細胞化学会  

CiNii Books

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その他リンク： http://search.jamas.or.jp/link/ui/2011331439

記述言語：日本語   出版者・発行元：日本組織細胞化学会  

CiNii Books

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記述言語：日本語   出版者・発行元：日本組織細胞化学会  

CiNii Books

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その他リンク： http://search.jamas.or.jp/link/ui/2011331438

記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：JAPAN ENDOCRINE SOC  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：SOC STUDY REPRODUCTION  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

DOI： 10.1016/j.neures.2010.07.1258

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記述言語：日本語   出版者・発行元：(公社)日本繁殖生物学会  

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記述言語：日本語   出版者・発行元：(公社)日本繁殖生物学会  

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記述言語：日本語   出版者・発行元：(公社)日本繁殖生物学会  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：SOC STUDY REPRODUCTION  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：SOC STUDY REPRODUCTION  

Web of Science

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記述言語：日本語   出版者・発行元：(公社)日本繁殖生物学会  

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記述言語：日本語   出版者・発行元：(一社)日本内分泌学会  

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記述言語：日本語   出版者・発行元：(公社)日本繁殖生物学会  

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記述言語：日本語   出版者・発行元：文永堂出版(株)  

J-GLOBAL

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記述言語：日本語   出版者・発行元：(公社)日本繁殖生物学会  

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記述言語：日本語   出版者・発行元：(公社)日本繁殖生物学会  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER IRELAND LTD  

Web of Science

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記述言語：日本語   出版者・発行元：(公社)日本繁殖生物学会  

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記述言語：日本語  

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記述言語：日本語  

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記述言語：日本語  

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記述言語：日本語  

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記述言語：日本語  

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記述言語：日本語  

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記述言語：日本語  

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