渗透性分子尿素通过诱导钙离子经二氢吡啶敏感性钙离子通道内流，刺激GH4C1细胞分泌催乳素。

The permeant molecule urea stimulates prolactin secretion in GH4C1 cells by inducing Ca2+ influx through dihydropyridine-sensitive Ca2+ channels.

作者信息

Sato N, Wang X B, Greer M A, Greer S E, McAdams S

机构信息

Department of Medicine, Oregon Health Sciences University, Portland 97201.

出版信息

Mol Cell Endocrinol. 1990 May 7;70(3):273-9. doi: 10.1016/0303-7207(90)90218-w.

DOI:10.1016/0303-7207(90)90218-w

PMID:2163337

Abstract

Isotonic urea in medium with a normal 1.2 mM Ca2+ concentration induced a striking rise in both cytosolic Ca2+ concentration ([Ca2+]i) and prolactin (PRL) secretion, each of whose peaks were proportional to the concentration of urea between 5 and 120 mM. There was a significant linear relationship between the peaks of induced [Ca2+]i and PRL secretion (r = 0.99, P less than 0.001). The increase in both [Ca2+]i and PRL secretion was completely abolished by removal of medium Ca2+ or by 2 microM nifedipine. Hypertonic urea was ineffective in inducing either an increase in [Ca2+]i or PRL secretion. These data support the hypothesis that plasma membrane expansion is a potent non-toxic inducer of hormone secretion and that in GH4C1 cells an increase in [Ca2+]i produced by enhanced influx of extracellular Ca2+ through dihydropyridine-sensitive Ca2+ channels plays an important role in this phenomenon.

摘要

在正常钙离子浓度为1.2 mM的培养基中，等渗尿素会引起细胞溶质钙离子浓度（[Ca2+]i）和催乳素（PRL）分泌显著升高，二者的峰值均与5至120 mM之间的尿素浓度成正比。诱导的[Ca2+]i峰值与PRL分泌峰值之间存在显著的线性关系（r = 0.99，P < 0.001）。去除培养基中的钙离子或使用2 microM硝苯地平可完全消除[Ca2+]i和PRL分泌的增加。高渗尿素无法诱导[Ca2+]i增加或PRL分泌。这些数据支持以下假说：质膜扩张是一种有效的无毒激素分泌诱导剂，在GH4C1细胞中，细胞外钙离子通过二氢吡啶敏感的钙离子通道内流增加导致的[Ca2+]i升高在这一现象中起重要作用。