Thompson D L, Garza F, St George R L, Rabb M H, Barry B E, French D D
Department of Animal Science, Louisiana State University Agricultural Center, Baton Rouge 70803.
Domest Anim Endocrinol. 1991 Apr;8(2):189-99. doi: 10.1016/0739-7240(91)90055-o.
Thirty-five ovariectomized pony mares were used to study the relationships among luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin (PRL) concentrations in blood (secretion), in pituitary (storage) and in blood after secretagogue administration, as well as the content of gonadotropin releasing hormone (GnRH) in hypothalamic areas, under various conditions of steroidal and nonsteroidal treatment. Five mares each were treated daily for 21 d with vegetable shortening (controls), testosterone (T; 150 micrograms/kg of body weight, BW), dihydrotestosterone (DHT; 150 micrograms/kg BW), estradiol (E2; 35 micrograms/kg BW), progesterone (P4; 500 micrograms/kg BW), dexamethasone (DEX; 125 micrograms/kg BW) or charcoal-stripped equine follicular fluid (FF; 10 ml). Secretagogue injections (GnRH and thyrotropin releasing hormone, TRH, at 1 and 4 micrograms/kg of BW, respectively) were given one d prior to treatment and again after 15 d of treatment. Relative to controls, treatment with T, DHT and DEX reduced (P less than .05) LH secretion, storage and response to exogenous GnRH, whereas treatment with E2 increased (P less than .05) these same characteristics. Treatment with P4 reduced (P less than .05) only LH secretion. Treatment with T, DHT, E2 and DEX reduced (P less than .05) FSH secretion, whereas treatment with P4 increased (P less than .05) it and FF had no effect (P greater than .1). All treatments increased (P less than .05) FSH storage, whereas only treatment with T and DHT increased (P less than .05) the FSH response to exogenous GnRH. Other than a brief increase (P less than .05) in PRL secretion in mares treated with E2, secretion of PRL did not differ (P greater than .1) among groups. Only treatment with E2 increased (P less than .01) PRL storage, yet treatment with T or DHT (but not E2) increased (P less than .05) the PRL response to exogenous TRH. Content of GnRH in the body and pre-optic area of the hypothalamus was not affected (P greater than .1) by treatment, whereas treatment with T, E2 and DEX increased (P less than .1) GnRH content in the median eminence. For LH, secretion, storage and response to exogenous GnRH were all highly correlated (r greater than or equal to .77; P less than .01). For FSH, only storage and response to exogenous GnRH were related (r = .62; P less than .01). PRL characteristics were not significantly related to one another. Moreover, the amount of GnRH in the median eminence was not related (P greater than .1) to any LH or FSH characteristic.
35匹去卵巢的母马被用于研究在甾体和非甾体治疗的各种条件下，血液（分泌）、垂体（储存）以及给予促分泌素后血液中促黄体生成素（LH）、促卵泡激素（FSH）和催乳素（PRL）浓度之间的关系，以及下丘脑区域促性腺激素释放激素（GnRH）的含量。每组5匹母马，每天分别用植物起酥油（对照组）、睾酮（T；150微克/千克体重，BW）、双氢睾酮（DHT；150微克/千克BW）、雌二醇（E2；35微克/千克BW）、孕酮（P4；500微克/千克BW）、地塞米松（DEX；125微克/千克BW）或经活性炭处理的马卵泡液（FF；10毫升）处理21天。在治疗前1天和治疗15天后分别给予促分泌素注射（GnRH和促甲状腺激素释放激素，TRH，分别为1和4微克/千克BW）。相对于对照组，用T、DHT和DEX治疗降低（P＜0.05）了LH的分泌、储存以及对外源GnRH的反应，而用E2治疗则增加（P＜0.05）了这些相同的特征。用P4治疗仅降低（P＜0.05）了LH的分泌。用T、DHT、E2和DEX治疗降低（P＜0.05）了FSH的分泌，而用P4治疗则增加（P＜0.05）了FSH的分泌，FF无影响（P＞0.1）。所有治疗均增加（P＜0.05）了FSH的储存，而仅用T和DHT治疗增加（P＜0.05）了FSH对外源GnRH的反应。除了用E2治疗的母马PRL分泌有短暂增加（P＜0.05）外，各组间PRL分泌无差异（P＞0.1）。仅用E2治疗增加（P＜0.01）了PRL的储存，但用T或DHT治疗（而非E2）增加（P＜0.05）了PRL对外源TRH的反应。治疗对下丘脑体内和视前区的GnRH含量无影响（P＞0.1），而用T、E2和DEX治疗增加（P＜0.1）了正中隆起处的GnRH含量。对于LH，分泌、储存以及对外源GnRH的反应均高度相关（r≥0.77；P＜0.01）。对于FSH，仅储存和对外源GnRH的反应相关（r = 0.62；P＜0.01）。PRL的各项特征之间无显著相关性。此外，正中隆起处的GnRH量与任何LH或FSH特征均无相关性（P＞0.1）。
