Differential Effects of Estradiol and Hydrocortisone on Liver Tryptophan Pyrrolase in Rats of Various Ages
Changes in the levels of certain regulatory enzymes and their indue-ibility by several hormones might account for the deterioration of physiological efficiency during aging in animals. Such changes may be brought about by the alterations in the template activity of their corresponding genes (Kanungo, 1975). Tryptophan pyrrolase (TP; L-tryptophan-oxygen 2, 3-oxidoreductase, E.C. 126.96.36.199) is a liver cytosolic enzyme that catalyzes the first and rate-limiting step in the degradation of tryptophan (Knox and Mehler, 1950), resulting in the synthesis of nicotinamide cofactors (Nish-izuka and Hayaishi, 1963). The present paper describes the activity and induction pattern of liver TP by estradiol and hydrocortisone in rats of different ages to elucidate molecular mechanisms of aging.
KeywordsHydrocortisone Glucocorticoid Tryptophan Estradiol Adenine
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