Negro-Vilar A, Culler M D, Masotto C
J Steroid Biochem. 1986 Nov;25(5B):741-7. doi: 10.1016/0022-4731(86)90303-1.
Reproductive function is regulated by an intricate system of peptide, steroid and amine factors interacting within the brain, pituitary and gonads. At no point is the complexity of the reproductive system better exemplified than in the exquisite interplay of factors required to produce and modulate pulsatile gonadotropin secretion. By extension, analysis of the pulsatile secretory pattern of the gonadotropins, as a means of assessing the contribution of these various factors, can reveal interactions too subtle to be detected by the conventional examination of mean gonadotropin concentration. Analysis of the pulsatile secretory patterns of both LH and FSH reveals striking differences between the two gonadotropins in their response to inhibitory, gonadal peptide and steroid factors, suggesting divergent paths of brain-pituitary regulation. Further studies to clarify this disparity in regulation have demonstrated that neutralization of endogenous LHRH completely abolishes pulsatile LH secretion without affecting pulsatile FSH secretion, suggesting the existence of another, as of yet unknown, brain factor which regulates FSH secretion. The feedback signals provided by gonadal steroids can induce both inhibition and facilitation of LHRH and LH secretion. Neurons of the central opiatergic system exert a tonic inhibitory influence on the catecholaminergic neurons regulating LHRH secretion, and are believed to mediate the inhibitory actions of the gonadal steroids on the LHRH system. Withdrawal of the gonadal steroids has been reported to cause a rapid loss of the tonic inhibitory control of the opiate system on LHRH secretion as revealed by a lack of response to naloxone. Reassessment of this system by analyzing the pulsatile pattern of LH secretion, however, reveals that the loss of naloxone effect after gonadectomy occurs very gradually and that an effect can still be obtained up to 2 weeks after the removal of gonadal steroids. These studies provide excellent examples of the complex interplay observed just between selected factors regulating pulsatile gonadotropin secretion. The use of pulsatile gonadotropin analysis is a powerful model, not only for providing greater clarity of known regulatory interactions, but also for revealing new and more subtle levels of control in the brain-pituitary-axis.
生殖功能受一个复杂的系统调节，该系统由肽、类固醇和胺类因子组成，它们在脑、垂体和性腺中相互作用。生殖系统的复杂性在产生和调节促性腺激素脉冲式分泌所需因子的精妙相互作用中体现得最为淋漓尽致。由此延伸，分析促性腺激素的脉冲式分泌模式，作为评估这些不同因子作用的一种手段，可以揭示一些过于微妙而无法通过传统的平均促性腺激素浓度检测来发现的相互作用。对促黄体生成素（LH）和促卵泡生成素（FSH）的脉冲式分泌模式进行分析，结果显示这两种促性腺激素在对抑制性、性腺肽和类固醇因子的反应上存在显著差异，这表明脑垂体调节存在不同路径。为阐明这种调节差异而开展的进一步研究表明，中和内源性促性腺激素释放激素（LHRH）会完全消除LH的脉冲式分泌，而不影响FSH的脉冲式分泌，这表明存在另一种尚未明确的脑因子来调节FSH分泌。性腺类固醇提供的反馈信号既能诱导对LHRH和LH分泌的抑制，也能诱导促进作用。中枢阿片能系统的神经元对调节LHRH分泌的儿茶酚胺能神经元施加持续性抑制影响，并且被认为介导了性腺类固醇对LHRH系统的抑制作用。据报道，去除性腺类固醇后，阿片系统对LHRH分泌的持续性抑制控制会迅速丧失，这表现为对纳洛酮无反应。然而，通过分析LH分泌的脉冲模式对该系统进行重新评估后发现，性腺切除术后纳洛酮效应的丧失非常缓慢，在去除性腺类固醇后长达2周仍能观察到效应。这些研究为调节促性腺激素脉冲式分泌的特定因子之间复杂的相互作用提供了绝佳例证。使用促性腺激素脉冲分析是一个强大的模型，不仅能更清晰地呈现已知的调节相互作用，还能揭示脑垂体轴中控制的新的、更微妙的层面。
