COMPARATIVE STUDIES ON THE METABOLISM OF OESTRADIOL IN THE BRAIN, THE PITUITARY AND THE LIVER OF THE RAT

Abstract

Radioactive estradiol was incubated with homogenates of hypothalamus, pituitary and liver and slices of cortex, hippocampus, hypothalamus, pituitary and liver of ovariectomized rats. 2- and 4-Substituted estrogens were the main metabolites in the brain and were found in the same proportions. In the liver only the 2-substituted estrogens were the main metabolites, while the 4-substituted ones were of minor quantitative importance. On the basis of wet weight the 2-hydroxylating capacity of the liver was approximately 50-fold greater than that of the brain and the 4-hydroxylating capacity about the same as that of the brain. Only slight differences in the 2- and 4-hydroxylating capacity of various brain areas were observed, although apparently the hypothalamus and the pituitary were more active in the formation of catecholestrogens than the cortex and the hippocampus.