McNeilly A S, Lincoln D W
J Endocrinol. 1983 Jun;97(3):401-7. doi: 10.1677/joe.0.0970401.
To investigate the role of the pineal gland in the long-term suppression of gonadotrophin secretion induced by prolactin, the effects of pinealectomy were studied in adult male rats with hyperprolactinaemia produced by the transplantation of two pituitary glands under the kidney capsule. Pinealectomy had no effect on basal levels of LH, FSH or prolactin. The presence of pituitary transplants induced a significant twofold increase in prolactin levels and a prolonged suppression in both LH and FSH. These changes were not affected by pinealectomy. Castration resulted in a similar rise in plasma levels of LH and FSH in rats with and without pituitary transplants. In control rats this rise in LH and FSH was reduced by testosterone-containing silicone elastomer implants (s.c) of 10 mm in length and delayed by implants of 30 mm. These rises in LH and FSH were significantly delayed (10-mm implant) or abolished (30-mm implant) in rats with pituitary transplants indicating an increase in sensitivity of the hypothalamic-pituitary axis to the negative feedback effects of testosterone in these animals compared to controls. These responses were not affected by pinealectomy. These results suggest that the pineal gland is not involved in the mechanism whereby pituitary grafts, possibly through their secretion of prolactin, cause long-term suppression of gonadotrophin secretion.
为了研究松果体在催乳素诱导的促性腺激素分泌长期抑制中的作用，我们在成年雄性大鼠中进行了松果体切除实验，这些大鼠因在肾囊下移植两个垂体而产生高催乳素血症。松果体切除对LH、FSH或催乳素的基础水平没有影响。垂体移植导致催乳素水平显著升高两倍，并使LH和FSH长期受到抑制。这些变化不受松果体切除的影响。去势导致有或没有垂体移植的大鼠血浆LH和FSH水平出现类似升高。在对照大鼠中，含睾酮的10毫米长硅胶弹性体植入物（皮下）可降低LH和FSH的这种升高，而30毫米长的植入物则使其延迟。在有垂体移植的大鼠中，LH和FSH的这些升高被显著延迟（10毫米植入物）或消除（30毫米植入物），这表明与对照相比，这些动物的下丘脑 - 垂体轴对睾酮负反馈作用的敏感性增加。这些反应不受松果体切除的影响。这些结果表明，松果体不参与垂体移植可能通过其分泌催乳素导致促性腺激素分泌长期抑制的机制。
