Effect of K+ on the phosphorylation of ribonucleoproteins in the adrenocortical tissue.
The effect of potassium ions on the phosphorylation of ribonucleoproteins (RNP) in guinea pig adrenocortical tissue was studied. Increase of K[^+] concentration in the incubation medium to 8.5 mmol/l, when stimulation of aldosterone production was observed, resulted in a decrease of membrane free RNP phosphorylation. Decrease in K[^+] concentration to 0.5 mmol/l caused the enhancement of label incorporation into the RNP. Staurosporine and phorbol ester raised the level of phosphorylation at 3.5 and 8.5 mmol/l K[^+]. The phosphate incorporation into membrane-bound polyribosomes was also enhanced, when the content of K[^+] in the medium was increased from 3.5 to 8.5 mmol/l, but removing of membranes by Triton X-100 resulted in a lowering of polyribosomes labeling. It is thus apparent that the phosphorylation or dephosphorylation of polyribosomes and RNP took part in the regulation of aldosterone biosynthesis by K[^+].
Poushkariov
VM
Institute of Endocrinology and Metabolism, Kiev 254114, Ukraine.
Prudiev
DP
Tronko
ND
Mikosha
AS