Tojo K, Kato Y, Ohta H, Matsushita N, Shimatsu A, Kabayama Y, Inoue T, Yanaihara N, Imura H
Endocrinology. 1985 Sep;117(3):1169-74. doi: 10.1210/endo-117-3-1169.
The effect of leumorphin (LM), one of big leu-enkephalins derived from preproenkephalin B, on PRL secretion was studied in the rat in vivo and in vitro. Intracerebroventricular injection of synthetic porcine LM (0.06-6 nmol/rat) caused a dose-related increase in plasma PRL levels in urethane-anesthetized male rats and in conscious freely moving rats. Intravenous injection of LM (3 nmol/100 g BW) also raised plasma PRL levels in these animals. The plasma PRL response to intracerebroventricular LM (0.6 nmol/rat) was blunted by naloxone (125 micrograms/100 g BW, iv). The stimulating effect of LM on PRL release was the most potent among the peptides derived from preproenkephalin B. In in vitro studies, PRL release from superfused anterior pituitary cells was stimulated in a dose-related manner by LM (10(-9)-10(-6) M), and the effect was blunted by naloxone (10(-5) M). These results suggest that LM has a potent stimulating effect on PRL secretion from the pituitary in the rat by acting, at least in part, directly at the pituitary through an opiate receptor.
亮啡肽（LM）是源自前脑啡肽原B的一种大亮氨酸脑啡肽，本研究在大鼠体内和体外观察了其对催乳素（PRL）分泌的影响。向脑室注射合成猪亮啡肽（0.06 - 6 nmol/大鼠）可使氨基甲酸乙酯麻醉的雄性大鼠和清醒自由活动大鼠的血浆PRL水平呈剂量依赖性升高。静脉注射亮啡肽（3 nmol/100 g体重）也可使这些动物的血浆PRL水平升高。纳洛酮（125微克/100 g体重，静脉注射）可减弱脑室注射亮啡肽（0.6 nmol/大鼠）引起的血浆PRL反应。在源自前脑啡肽原B的肽类中，亮啡肽对PRL释放的刺激作用最为显著。在体外研究中，亮啡肽（10⁻⁹ - 10⁻⁶ M）可剂量依赖性刺激灌流的垂体前叶细胞释放PRL，且该作用可被纳洛酮（10⁻⁵ M）减弱。这些结果表明，亮啡肽至少部分通过阿片受体直接作用于垂体，对大鼠垂体PRL分泌具有强大的刺激作用。
