Resko J A, Horton L E
Endocrinology. 1983 Mar;112(3):850-5. doi: 10.1210/endo-112-3-850.
The effects of progesterone (P) on estrogen (E)-induced gonadotropin release were studied in 10 adult male rhesus macaques castrated more than 2 yr earlier. The intent was to determine whether physiological levels of P (approximately 400 pg/ml) found in the systemic circulation of intact males would block E-induced gonadotropin release and whether the responses of castrated males were similar to those of castrated females with and without pretreatment with 17 beta-estradiol (E2). Different doses of P were administered in Silastic capsules (0.3, 4.0, and 5.0 cm) implanted sc. A 0.3-cm implant maintained serum P levels at about 400 pg/ml (equivalent to physiological levels in intact males); 5.0-cm implants produced serum levels of about 4.0 ng/ml (similar to luteal phase levels in females). In male monkeys treated for approximately 3 weeks with E2, only the highest dose (approximately 4.0 ng/ml) of P blocked FSH induced by estradiol benzoate (E2B). LH was blocked in one third of the animals thus treated. The same P dose was ineffective in blocking E2-induced LH release in spayed females pretreated with E2, but did block FSH release. Gonadectomized males and females not treated beforehand with E2 released LH in response to an E2B challenge, but FSH was not elevated in the peripheral circulation under these experimental conditions. These results suggest that luteal phase levels of P block E2-induced FSH release in gonadectomized males and females. With the same treatment regimens, P blocks E2 action in some males, but all females responded to E2B by releasing LH. These data also suggest that estrogen priming is necessary for FSH, but not LH, release in adult rhesus macaques of both sexes. The prerequisite of E treatment for the induction of positive feedback appears to be associated with the level of gonadotropin suppression before E2B treatment.
在10只2年多以前就已阉割的成年雄性恒河猴中，研究了孕酮（P）对雌激素（E）诱导的促性腺激素释放的影响。目的是确定完整雄性动物体循环中发现的生理水平的P（约400 pg/ml）是否会阻断E诱导的促性腺激素释放，以及阉割雄性动物的反应是否与经17β-雌二醇（E2）预处理和未预处理的阉割雌性动物相似。不同剂量的P通过皮下植入的硅橡胶胶囊（0.3、4.0和5.0 cm）给药。一个0.3 cm的植入物可使血清P水平维持在约400 pg/ml（相当于完整雄性动物的生理水平）；5.0 cm的植入物可使血清水平达到约4.0 ng/ml（类似于雌性动物黄体期水平）。在用E2处理约3周的雄性猴子中，只有最高剂量（约4.0 ng/ml）的P能阻断苯甲酸雌二醇（E2B）诱导的促卵泡激素（FSH）释放。三分之一接受该处理的动物的促黄体生成素（LH）被阻断。相同剂量的P对经E2预处理的去卵巢雌性动物阻断E2诱导的LH释放无效，但能阻断FSH释放。事先未用E2处理的去性腺雄性和雌性动物在接受E2B刺激后会释放LH，但在这些实验条件下，外周循环中的FSH并未升高。这些结果表明，黄体期水平的P可阻断去性腺雄性和雌性动物中E2诱导的FSH释放。采用相同的治疗方案时，P可阻断部分雄性动物中的E2作用，但所有雌性动物均通过释放LH对E2B作出反应。这些数据还表明，雌激素预处理对于成年恒河猴两性FSH的释放是必要的，但对于LH的释放并非必要。E处理诱导正反馈的先决条件似乎与E2B处理前促性腺激素的抑制水平有关。
