Phosphorylation in vivo of rat hepatic glucocorticoid receptor.

Rat liver glucocorticoid receptors were labeled in vivo with [32P]orthophosphate. In the last two fractionation procedures leading to purified, molybdate-stabilized, unactivated receptor complex, bound [32P] coeluted with peaks of bound [3H]triamcinolone acetonide. SDS-gel electrophoresis revealed [32P] labeled 90K and 24K bands. The lower molecular weight band is heavily phosphorylated and it could be either a component of the unactivated receptor or a degradation product.