Role of Neuropeptides in Regulating the Secretion of Growth Hormone and Prolactin

垂体腺分泌生长激素(GH)和催乳素(PRL)受多种下丘脑因素的调节，这些因素主要是神经肽和生物胺。我们发现，5-羟色胺诱导的GH和PRL分泌是由下丘脑GRF和VIP介导的。甘丙素可刺激大鼠生长激素和催乳素的分泌。我们发现，α-肾上腺素能和阿片能机制参与了甘丙肽诱导的催乳素释放。此外，还证实了甘丙素与5-羟色胺在PRL分泌中的相互作用。甘丙肽诱导的GH分泌是由下丘脑GRF介导的。另一方面，内源性多巴胺和生长抑素抑制催乳素和生长激素的分泌。GRP刺激下丘脑释放多巴胺和生长抑素。这些发现表明神经肽在调节垂体激素中具有重要而复杂的作用，并提示这种神经肽的有效和长效类似物可能在治疗中用于协调调节垂体肿瘤的功能。

The secretion of Growth Hormone (GH) and prolactin (PRL) from the pituitary is regulated by a variety of hypothalamic factors, which are mostly neuropeptides and biogenic amines. We found that GH and PRL secretion induced by serotonin is mediated by hypothalamic GRF and VIP. Galanin stimulates both GH and PRL secretion in the rat. We found that alpha-adrenergic and opioidergic mechanisms are involved in PRL release induced by galanin. Furthermore, the interaction of galanin with serotonin in PRL secretion was also demonstrated. GH secretion induced by galanin is mediated by hypothalamic GRF. On the other hand, PRL and GH secretion is inhibited by endogenous dopamine and somatostatin. GRP stimulates both dopamine and somatostatin release from the hypothalamus. These findings indicate an important and complicated role of neuropeptides in regulating pituitary hormones and suggest a possible therapeutic use of a potent and long-actinf analogue of such neuropeptides in cosistently modulating the function of pituitary tumors.