生长抑素对离体大鼠胰岛中3',5'-环磷酸腺苷依赖性蛋白激酶激活的影响。

The effect of somatostatin on the activation of adenosine 3',5'-monophosphate-dependent protein kinase in isolated rat islets of Langerhans.

作者信息

Oliver J R, Kemp B E

出版信息

Endocrinology. 1980 Apr;106(4):1259-64. doi: 10.1210/endo-106-4-1259.

Abstract

Somatostatin has been reported to inhibit the increases in cAMP levels induced by glucagon in isolated islets of Langerhans. The present study was undertaken to test whether the reported effects of somatostatin on islet cAMP levels were also reflected in changes in the cAMP-dependent protein kinase activity. Isolated islets were found to contain both isoenzymes of the cAMP-dependent protein kinase. In the presence of theophylline (2 mM), glucagon (2.9 X 10(-6) M) increased the islet protein kinase activity ratio from 0.24 +/- 0.02 to 0.55 +/- 0.02. Somatostatin (6.6 X 10(-7) M) fully inhibited both the glucagon (2.9 X 10(-7) M)- and theophylline (2 mM)-induced increases in the protein kinase activity ratio. Omission of Ca2+ from the islet incubation media did not alter the inhibitory effect of somatostatin on the glucagon-dependent activation of the cAMP-dependent protein kinase. The present study has demonstrated that in the islets of Langerhans, glucagon-dependent activation of the cAMP-dependent protein kinase can be modulated by somatostatin.

摘要

据报道，生长抑素可抑制胰高血糖素在分离的胰岛中诱导的环磷酸腺苷（cAMP）水平升高。本研究旨在测试生长抑素对胰岛cAMP水平的上述作用是否也反映在cAMP依赖性蛋白激酶活性的变化上。研究发现，分离的胰岛中含有cAMP依赖性蛋白激酶的两种同工酶。在茶碱（2 mM）存在的情况下，胰高血糖素（2.9×10⁻⁶ M）使胰岛蛋白激酶活性比值从0.24±0.02升高至0.55±0.02。生长抑素（6.6×10⁻⁷ M）完全抑制了胰高血糖素（2.9×10⁻⁷ M）和茶碱（2 mM）诱导的蛋白激酶活性比值升高。从胰岛孵育培养基中去除钙离子（Ca²⁺）并不会改变生长抑素对胰高血糖素依赖性激活cAMP依赖性蛋白激酶的抑制作用。本研究表明，在胰岛中，生长抑素可调节胰高血糖素依赖性激活cAMP依赖性蛋白激酶。