Inhibition by 1-(5-isoquinolinesulfonyl)-2-methylpiperazine, an inhibitor of protein kinase C, of enzyme induction by glucocorticoid and of nuclear translocation of glucocorticoid-receptor complexes.

Induction of tyrosine aminotransferase by glucocorticoid in rat hepatocytes was inhibited concentration-dependently by 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7), an inhibitor of protein kinase C, but not by N- [2-(methyl-amino)-ethyl]-5-isoquinolinesulfonamide dihydrochloride, an inhibitor of cyclic nucleotide dependent protein kinases. H-7 also inhibited the accumulation of glucocorticoid-receptor complexes in the nuclear fraction with associated accumulation of these complexes in the cytoplasmic fraction, but did not affect incorporation of glucocorticoid into hepatocytes. These results indicate that protein kinase C may be essential in translocation of glucocorticoid-receptor complexes to the nuclei.