Abstract

Administration of triamcinolone diacetate to rats results in a decrease of prolyl hydroxylase activity in organs from animals of different ages. The response of the enzyme activity is dose-dependent, reversible, independent of endocrine function (except for the response of the liver enzyme in hypophysectomized rats), and dependent on the number of daily injections. The decrease in enzyme activity is paralleled by a decrease in the amount of enzyme protein as measured by immunoassay. These results indicate that prolyl hydroxylase is decreased in a wide spectrum of tissues following administration of anti-inflammatory steroids. Furthermore, these findings suggest that one of the effects of this class of therapeutically used drugs on connective tissue metabolism may be mediated by a decrease in the prolyl hydroxylation step of collagen biosynthesis.