- 著者
- Shun Sato Chengzhu Yin Akira Teramoto Yasuo Sakuma Masakatsu Kato
- 出版者
- PHYSIOLOGICAL SOCIETY OF JAPAN
- 雑誌
- The Journal of Physiological Sciences (ISSN:18806546)
- 巻号頁・発行日
- vol.58, no.5, pp.317-322, 2008 (Released:2008-10-29)
- 参考文献数
- 47
- 被引用文献数
- 7 16
Gonadotropin-releasing hormone (GnRH) neurons represent the final output neurons in the central control of reproduction. γ-Amino butyric acid (GABA), one of the major regulators of GnRH neurons, depolarizes GnRH neurons isolated from adult rats via GABAA receptors. The presence of GABAA receptors in GnRH neurons has also been demonstrated morphologically. Furthermore, the pineal hormone melatonin is involved in the regulation of reproductive function, including the timing of the luteinizing hormone surge. The suprachiasmatic nucleus and the GABAergic system in the medial preoptic area are considered as possible sites of the action of melatonin. Until now, however, a direct action of melatonin on GnRH neurons has not been reported. Therefore we examined the effect of melatonin on GABAA receptor currents in GnRH neurons isolated from GnRH-EGFP transgenic rats by means of perforated patch-clamp experiments. The GABAA receptor currents were modulated by melatonin in a sex-specific manner. In GnRH neurons from adult males, melatonin augmented these currents in 67% of the neurons examined, but attenuated the currents in only 19% of them. These modulations were blocked by the melatonin receptor antagonist luzindole, suggesting an involvement of melatonin receptors. The modulation by melatonin was not observed in GnRH neurons isolated from infantile rats. These findings indicate that GABA affects the excitability of GnRH neurons in adult rats through GABAA receptors, and that melatonin modifies this excitability via melatonin receptors in a sex-specific manner.
- 著者
- Akira Shimatsu Noriyuki Iwamoto Toshiaki Tanaka Akira Teramoto Masanori Taketsuna Katsuichiro Ihara Jumpei Funai Minoru Irie Kazuo Chihara
- 出版者
- (社)日本内分泌学会
- 雑誌
- Endocrine Journal (ISSN:09188959)
- 巻号頁・発行日
- vol.62, no.8, pp.749-756, 2015 (Released:2015-08-29)
- 参考文献数
- 27
In addition to impaired physical activity, adult GH deficiency (GHD) can decrease quality of life (QOL). Hence, assessment of QOL is important to evaluate the efficacy of GH replacement therapy. This study aimed to identify factors that may be predictive of long-term improvement in QOL among clinical/laboratory variables during GH replacement therapy. The analysis included 83 Japanese adults with GHD who participated in the Hypopituitary Control and Complications Study (HypoCCS). Correlations between the change from baseline in clinical/laboratory variables at 6 months and the change from baseline in Quality of life (Short-Form 36 [SF-36] component scores) at 12 months were examined. Unexpectedly, all component scores were negatively correlated with the change in fasting plasma glucose concentration (FPG) (physical component summary [PCS], r = -0.456; mental component summary [MCS], r = -0.523; role/social component summary [RCS], r = -0.433). The change in MCS was positively correlated with the change in insulin-like growth factor-1 standard deviation score (IGF-1 SDS) (r = 0.417). The change in PCS was positively correlated with the change in body fat (r = 0.551). The change in RCS was positively correlated with the change in waist circumference (r = 0.528). Short-term changes in several clinical/laboratory variables, most notably FPG and IGF-1 SDS, were correlated with long-term changes in QOL. The clinical importance of these correlations for predicting GH replacement treatment efficacy warrants further investigation.
- 著者
- Yasushi HARA Takahiro TESHIMA Takahiro TAODA Hirokazu ISHINO Yoshinori NEZU Yasuji HARADA Takuya YOGO Hiroyuki MASUDA Akira TERAMOTO Masahiro TAGAWA
- 出版者
- 公益社団法人 日本獣医学会
- 雑誌
- Journal of Veterinary Medical Science (ISSN:09167250)
- 巻号頁・発行日
- vol.72, no.4, pp.397-404, 2010 (Released:2010-05-03)
- 参考文献数
- 53
- 被引用文献数
- 4 13
Postoperative changes in endocrinological status and serum chemistry during the 4 years after transsphenoidal surgery (TSS) in 25 dogs with Cushing's disease were investigated in a prospective study. In all 25 dogs, Cushing's disease was diagnosed from resected pituitary tissues as a corticotroph adenoma in the anterior lobe of the pituitary. Prior to TSS, all 25 dogs showed hypercortisolemia. After TSS, the ACTH stimulation test showed continued low serum cortisol concentrations in 21 dogs (84%). In addition, the serum thyroid stimulating hormone concentrations decreased sequentially, while the serum T4 concentrations tended to increase due to the postoperative hormone substitution therapy utilized to avoid secondary hypothyroidism. In regard to serum chemistry, alkaline phosphatase (ALP), alanine aminotransferase (ALT) and total cholesterol are commonly increased in canine Cushing's disease. In this study, ALP, ALT and total cholesterol were increased in 23 cases (92%), 19 cases (76%) and 20 cases (80%), respectively. However, postoperatively, these concentrations gradually decreased. The postoperative serum concentrations of ALP at 1 year, that of ALT at six months to 2 years and that of total cholesterol over the course of the 4 years decreased significantly compared with the concentrations before TSS. These results show that TSS is an effective treatment for canine Cushing's disease and for long-term improvement of hypercortisolemia. Moreover, TSS is effective in improvement of hypercortisolism, such as increased concentrations of serum ALP, ALT and total cholesterol.
- 著者
- Takahiro TESHIMA Yasushi HARA Kae SHIGIHARA Susumu TAKEKOSHI Yoshinori NEZU Yasuji HARADA Takuya YOGO Akira TERAMOTO Robert Y. OSAMURA Masahiro TAGAWA
- 出版者
- 公益社団法人 日本獣医学会
- 雑誌
- Journal of Veterinary Medical Science (ISSN:09167250)
- 巻号頁・発行日
- vol.71, no.1, pp.93-98, 2009 (Released:2009-02-05)
- 参考文献数
- 36
- 被引用文献数
- 5 8 1
Pituitary thyrotroph hyperplasia results from prolonged primary hypothyroidism in humans, mice and rats. In dogs with Cushing's disease, many cases have low serum thyroid hormones concentrations due to euthyroid sick syndrome. A 6-year-old castrated male Beagle diagnosed with Cushing's disease had a high serum thyroid stimulating hormone (TSH) concentration that was treated by hypophysectomy. On histological examination, the resected pituitary gland contained both a corticotroph adenoma and thyrotroph hyperplasia. The TSH-positive cell ratio in this case was greater than that of healthy Beagles. In the present case, the pituitary thyrotroph hyperplasia was probably caused by primary hypothyroidism. In conclusion, this Beagle is the first histological confirmation of the coexistence of a corticotroph adenoma and thyrotroph hyperplasia.