H-7 reduces the nuclear binding of [3H]dexamethasone in rat liver slices but does not affect the phosphorylation of glucocorticoid receptor.

The effect of 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7), an inhibitor of protein kinase C, on the nuclear binding of [3H]dexamethasone and on the phosphorylation of glucocorticoid receptor was studied in rat liver slices to ascertain the role of protein kinase C in the expression of glucocorticoid action. H-7 reduces the nuclear binding of [3H]dexamethasone in rat liver slices. It does not affect the extent of phosphorylation of glucocorticoid receptor both in the absence or in the presence of glucocorticoid. These findings indicate that protein kinase C may be involved in the nuclear binding of glucocorticoid receptor but does not directly influence the receptor phosphorylation.