Effect of hydrocortisone and desoxycorticosterone on some reductases, esterases and synthetases.

Corticosteroids, applied in single high doses, are known to inhibit the activity of mixed function oxidases. Experiments on male rats have been performed in order to clarify their effect on other drug-metabolizing enzyme systems. It is found that hydrocortisone (HC) and desoxycorticosterone (DOCA), applied in a single dose of 50 mg/kg, do not change the activity of the liver microsomal NADPH-dependent neotetrazolium reductase. HC inhibits the intestinal acetylsalicylic esterase B, whereas DOCA does not change it significantly. This effect should be borne in mind when combining corticosteroids with acetysal. No significant changes are observed in the activity of liver esterase A under the effect of the two corticosteroids. DOCA inhibits the liver cytosol glutathione-S-transferase. The reduced enzyme activity of the liver microsomal UDP-glucuronyl-transferase by the two corticosteroids and of the glutathione-S-transferase by HC is manifested only as an insignificant tendency.