The participation of cAMP and protein kinase C in the regulation of aldosterone biosynthesis by potassium.
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.
Pushkarev
V M
VM
Institute of Endocrinology and Metabolism, Academy of Sciences of the Ukrainian SSR, Kiev.
Mikosha
A S
AS
D000302:Adrenal Cortex / Q000187:drug effects / Q000378:metabolism*; D000450:Aldosterone / Q000096:biosynthesis*; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D002746:Chlorpromazine / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology*; D003600:Cytosol / Q000201:enzymology; D004492:Edetic Acid / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007700:Kinetics; D007811:Lanthanum / Q000494:pharmacology; D008297:Male; D011188:Potassium / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism*
D000450:Aldosterone; D004533:Egtazic Acid; D007811:Lanthanum; D004492:Edetic Acid; D000242:Cyclic AMP; D011493:Protein Kinase C; D011188:Potassium; D002746:Chlorpromazine