在GH4C1细胞中，胞质Ca2+的增加速率而非幅度调节由去极化K+或低渗诱导的催乳素分泌程度。

The rate of increase not the amplitude of cytosolic Ca2+ regulates the degree of prolactin secretion induced by depolarizing K+ or hyposmolarity in GH4C1 cells.

作者信息

Sato N, Wang X B, Greer M A

机构信息

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

出版信息

Biochem Biophys Res Commun. 1990 Jul 31;170(2):968-72. doi: 10.1016/0006-291x(90)92186-4.

DOI:10.1016/0006-291x(90)92186-4

PMID:2383277

Abstract

Depolarizing K+ and medium hyposmolarity caused striking rises in both cytosolic free Ca2+ concentration [( Ca2+]i) and prolactin (PRL) secretion in GH4C1 cells, which were completely blocked by removal of medium Ca2+. However, the increase in [Ca2+]i and PRL secretion induced by hyposmolarity was clearly slower than that induced by K+. Although there was a good correlation between the zenith of PRL secretion and [Ca2+]i induced by various intensities of K+ or hyposmolarity, the regression slopes were significantly different between the K(+)-and hyposmolarity-induced changes (P less than 0.01). There was a good correlation between the maximum rate of change in PRL secretion and that of the increase in [Ca2+]i when the data from the 2 secretagogues were combined (r = 0.994, P less than 0.001, N = 9). We suggest that the rate of increase in [Ca2+]i may be more important than the amplitude of [Ca2+]i in stimulating PRL secretion.

摘要

去极化钾离子和低渗培养基可使GH4C1细胞的胞质游离钙离子浓度[Ca2+]i和催乳素（PRL）分泌显著升高，去除培养基中的钙离子可完全阻断这一现象。然而，低渗培养基诱导的[Ca2+]i升高和PRL分泌明显慢于钾离子诱导的变化。尽管不同强度的钾离子或低渗培养基诱导的PRL分泌峰值与[Ca2+]i之间存在良好的相关性，但钾离子和低渗培养基诱导的变化之间的回归斜率存在显著差异（P<0.01）。当将两种促分泌剂的数据合并时，PRL分泌的最大变化率与[Ca2+]i升高的最大变化率之间存在良好的相关性（r = 0.994，P<0.001，N = 9）。我们认为，在刺激PRL分泌方面，[Ca2+]i的升高速率可能比其幅度更为重要。