胃泌素释放肽调节前叶垂体催乳素和β-内啡肽分泌的研究

Gastrin-Releasing Peptide Regulates Secretion of β-Endorphin and Prolactin in Anterior Pituitary

在清醒自由活动的SD雄性大鼠中,第三脑室内微量注射胃泌素释放肽(GRP)0.7和2.0μg后,兴奋前叶垂体β-内啡肽(β-EP)的静启分泌;2.0μg GRP可进一步兴奋限制性应激引起的β-EP释放。上述两个剂量的GRP都抑制催乳素(PRL)的静息分泌和应激时PRL的释放。 在离体培养的前叶垂体细胞中,0.5和1.0μg的GRP都兴奋B-EP和PRL的分泌。结果提示,GRP抑制PRL释放的作用地点在下丘脑,而GRP兴奋β-EP释放的作用地点可能在下丘脑或直接作用于垂体。

The objective of this study was to datarmine the possible effects of gastrin-rele-asing peptide ( GRP ) onβ-endorphin anb .prolactin in anterior pituitary and primary analysis of central and peripheral mechanism of the action.Synthetic porcine GRP ( 1 -27 ) was injected intraventricularly ( third ventricular, 0.7 and 2.0μS/3μl) in conscious rats bearing an intrajugular cannula. A significant increase in resting and restraint stress-induced release of β -endorphin (β-EP)and a significant decrease in resting and stress-induced release of prolactin ( PRL ) were observed after the injection of GRP.To determine if GRP had any direct action on the pituitary, in vitro incubation of dispersed anterior pituitary cells of rat with 0.05, 0.5 and 1.0 μg GRP increased β-EP and PRL secretion.These deta suggest that inhibitory effect of GRP on resting and stress-induced release of PRL may be within hypothalamus, whereas GRP stimulates β-endorphin release at both sites of hypothalamus and anterior pituitary.