Esquifino A I, Villanúa M A, Agrasal C, Tresguerres J A
Departamento de Bioquimíca, Facultad de Medicina, Universidad Complutense, Madrid, Spain.
Pharmacol Biochem Behav. 1989 Jan;32(1):157-62. doi: 10.1016/0091-3057(89)90226-8.
Melatonin administration to pituitary-grafted male and female rats resulted in a marked decrease of previously high plasma prolactin levels, while an increase in prolactin levels was observed in sham-operated controls. The latter effect was significant only in males. Treatment with melatonin did not modify basal LH hormone levels or LH responses to luteinizing hormone-releasing hormone (LHRH) in sham-operated rats of either sex. However, in pituitary-grafted females, melatonin increased both basal and LHRH-stimulated LH levels towards values recorded in sham-operated controls. No effects on basal LH levels were detected in grafted males under melatonin treatment, but the response of LH to LHRH was markedly increased and no longer differed from the values measured in sham-operated control animals pretreated with saline. Melatonin did not affect follicle stimulating hormone (FSH) levels except for an increase in FSH response to LHRH in grafted females. These findings suggest the existence of sex-dependent effects of melatonin on LH and FSH secretions. These effects of melatonin may be mediated by the different plasma prolactin levels in pituitary-grafted and sham-operated rats.
给移植了垂体的雄性和雌性大鼠注射褪黑素后，之前较高的血浆催乳素水平显著降低，而在假手术对照组中观察到催乳素水平升高。后一种效应仅在雄性中显著。褪黑素处理对假手术的两性大鼠的基础促黄体生成素（LH）激素水平或LH对促黄体生成素释放激素（LHRH）的反应没有影响。然而，在移植了垂体的雌性大鼠中，褪黑素使基础LH水平和LHRH刺激的LH水平均升高至假手术对照组记录的值。在接受褪黑素处理的移植雄性大鼠中，未检测到对基础LH水平的影响，但LH对LHRH的反应显著增加，且与用盐水预处理的假手术对照动物测量的值不再有差异。褪黑素除了使移植雌性大鼠中FSH对LHRH的反应增加外，对促卵泡生成素（FSH）水平没有影响。这些发现表明褪黑素对LH和FSH分泌存在性别依赖性效应。褪黑素的这些效应可能由移植了垂体的大鼠和假手术大鼠中不同的血浆催乳素水平介导。
