Bhagat L, Duraiswami S, Muralidhar K
Department of Zoology, University of Delhi, India.
J Pineal Res. 1994 May;16(4):193-7. doi: 10.1111/j.1600-079x.1994.tb00101.x.
Both melatonin and pineal antigonadotropic peptides have the same end effect, i.e., prevention of the hypertrophic response when tested in the conventional compensatory ovarian hypertrophy (COH) model. The present work was undertaken to study the effect of melatonin and a melatonin- and steroid-free inhibin-like ovine pineal antigonadotropin (PI) on serum follicle stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL) following hemoiovariectomy in adult Holtzman rats and also to ascertain if any similarity exists in their mode of action during COH. While melatonin prevented the transient rise in FSH at 12 hr after unilateral ovariectomy (ULO), thus retaining the basal preoperative level, PI depressed basal levels of FSH too. In addition, melatonin suppressed PRL and LH levels at 12 hr and 120 hr after ULO, respectively. PI, on the other hand, had no effect on serum LH and PRL levels. In light of our earlier in vitro results, which showed a direct inhibitory effect of PI and not of melatonin on pituitary FSH synthesis and release, the present results indicate a dichotomy in the mode of action of PI and melatonin. PI acts directly at the level of the pituitary while melatonin may act at the level of the hypothalamus or higher brain centers to suppress the FSH surge and the ensuing compensatory response.
褪黑素和松果体抗促性腺激素肽具有相同的最终作用效果，即在传统的代偿性卵巢肥大（COH）模型中进行测试时，可预防肥大反应。本研究旨在探讨褪黑素和一种不含褪黑素及类固醇的抑制素样绵羊松果体抗促性腺激素（PI）对成年霍尔兹曼大鼠血液卵巢切除术后血清卵泡刺激素（FSH）、黄体生成素（LH）和催乳素（PRL）的影响，并确定它们在COH过程中的作用模式是否存在相似性。虽然褪黑素可预防单侧卵巢切除术后12小时FSH的短暂升高，从而维持术前基础水平，但PI也会降低FSH的基础水平。此外，褪黑素分别在单侧卵巢切除术后12小时和120小时抑制PRL和LH水平。另一方面，PI对血清LH和PRL水平没有影响。根据我们早期的体外实验结果，即PI而非褪黑素对垂体FSH的合成和释放具有直接抑制作用，目前的结果表明PI和褪黑素的作用模式存在差异。PI直接作用于垂体水平，而褪黑素可能作用于下丘脑或更高的脑中枢水平，以抑制FSH激增及随后的代偿反应。
