Murphy B D, DiGregorio G B, Douglas D A, González-Reyna A
Department of Obstetrics and Gynecology, University of Saskatchewan, Saskatoon, Canada.
J Reprod Fertil. 1990 Jul;89(2):423-9. doi: 10.1530/jrf.0.0890423.
Immature female mink, 8 weeks of age in July, were treated with implants releasing melatonin. Mating, which induced ovulation, took place during the normal breeding season in the following March. Circulating prolactin and progesterone concentrations did not undergo the expected gestational increases, and no embryos implanted. A similar absence of gestational changes in prolactin and progesterone values ensued in primiparous mink treated with the melatonin implant 2-3 days after the second of 2 matings. Administration of exogenous sheep prolactin (0.5 mg/day) by minipump induced precocious elevation of progesterone concentrations in mated mink. Prolactin administration overcame the effects of melatonin, in that the corpora lutea were activated and embryos implanted, but exogenous prolactin resulted in degeneration of implanted embryos both in the presence and absence of chronic melatonin. The results suggest that melatonin has a single effect in alteration of gestation in mink; i.e. the prevention of prolactin secretion. Hyperprolactinaemia may inhibit embryo development in this species.
7月时，对8周龄的未成年雌性水貂植入释放褪黑素的植入物进行处理。次年3月正常繁殖季节时进行诱导排卵的交配。循环中的催乳素和孕酮浓度未出现预期的孕期升高，且未发生胚胎着床。在两次交配中的第二次交配后2 - 3天对初产水貂植入褪黑素植入物，催乳素和孕酮值也同样未出现孕期变化。通过微型泵给予外源性绵羊催乳素（0.5毫克/天）可使交配后的水貂孕酮浓度早熟性升高。催乳素给药克服了褪黑素的作用，因为黄体被激活且胚胎着床，但无论是否存在慢性褪黑素，外源性催乳素都会导致着床胚胎退化。结果表明，褪黑素对水貂妊娠改变具有单一作用；即抑制催乳素分泌。高催乳素血症可能会抑制该物种的胚胎发育。
