AGE AND GENDER EFFECT ON THE INDUCIBILITY OF STEROID METABOLIZING CYTOCHROME-P450 IN RAT-LIVER

Liver microsomal steroid hydroxylases and 5 alpha reductase activities were evaluated by quantitation of specific metabolites from 4-C-14 pr ogesterone after TLC separation. Each enzyme showed a different develo pmental profile depending on the gender of the rat. Dexamethasone indu ced both 6 beta and 16 alpha progesterone hydroxylase, being more pote nt for 6 beta (3 to 4 folds) than 16 alpha (1.2 to 1.6 folds). A compa rison of the inducibility of 6 beta and 16 alpha hydroxylase by dexame thasone in rats from different age groups showed that for both enzymes , the degree of increase was higher in the younger than older groups. Thus there is a blunting in the responsiveness to dexamethasone induct ion of both 6 beta and 16 alpha hydroxylase with age particularly in f emale animals. This decrease in responsiveness in older females could potentially affect their capacity to metabolize endogenous and exogeno us agents.