Pushkarev V M, Mikosha A S
Institute of Endocrinology and Metabolism, Academy of Sciences of the Ukrainian SSR, Kiev.
Biomed Sci. 1991;2(2):135-9.
The mechanism of the effect of potassium ions (K+) on aldosterone production in guinea pig adrenal cortex was examined. At high K+ concentrations (approximately 8 mM) in the incubation media, aldosterone output and content was elevated, and there was a significant increase in the phosphorylation of intracellular proteins and of protein kinase C activity. Cyclic AMP levels showed a less significant increase. EGTA and lanthanum ions (La3+), and also chlorpromazine with regard to protein phosphorylation, appeared to remove the effect of raised K+ concentrations on steroidogenesis and protein phosphorylation. At low K+ concentrations, addition of EGTA led to a significant accumulation of cyclic AMP. Evidence that steroidogenesis is regulated by a cyclic-AMP-dependent mechanism at low K+ levels is presented, and we also report the first direct evidence of activation of aldosterone synthesis by protein kinase C at high K+ concentration.
研究了钾离子（K +）对豚鼠肾上腺皮质醛固酮分泌影响的机制。在孵育培养基中高钾浓度（约8 mM）时，醛固酮产量和含量升高，细胞内蛋白质磷酸化和蛋白激酶C活性显著增加。环磷酸腺苷（cAMP）水平升高不太显著。乙二醇双（2-氨基乙基醚）四乙酸（EGTA）和镧离子（La3 +），以及就蛋白质磷酸化而言的氯丙嗪，似乎消除了升高的钾浓度对类固醇生成和蛋白质磷酸化的影响。在低钾浓度下，添加EGTA导致cAMP显著积累。提出了在低钾水平时类固醇生成受环磷酸腺苷依赖性机制调节的证据，并且我们还报告了在高钾浓度下蛋白激酶C激活醛固酮合成的首个直接证据。
