Formation of 2- and 4-hydroxyestrogens by brain, pituitary, and liver of the human fetus.
When [6,7-3H]estradiol was incubated with tissue homogenates of the brain, the pituitary, and the liver of two human female fetuses, a number of radioactive metabolites more "polar" than the incubated substrate were detected. Among these, the identification of two types of catecholestrogens, i.e. the 2- and 4-hydroxyestrogens, was of major interest. Compared on the basis of wet weight of tissues (250 mg), the conversion of estradiol to 2-hydroxyestrogens (2-hydroxyestradiol and 2-hydroxyestrone) was 0.8% in the frontal cortex, 1.0% in the hypothalamus, 2.1% in the pituitary, and 7.8% in the liver. For the first time, the formation of 4-hydroxyestrogens was demonstrated. The percentages of incubated estradiol hydroxylated at C-atom 4 (4-hydroxyestradiol and 4-hydroxyestrone) were 0.5 in the cortex, 0.4% in the hypothalamus, .1% in the pituitary, and 0.5% in the liver. The results show that fetal brain and pituitary tissue can hydroxylate estradiol in positions 2 and 4 to a similar extent, whereas in the liver, about 15 times more 2-hydroxy than 4-hydroxy compounds are formed. Moreover, the 2-hydroxylating capacity of the liver is definitely greater than that of the brain, whereas the 4-hydroxylating capacity is about the same as that of the brain.
D001921:Brain / Q000196:embryology* / Q000378:metabolism; D004958:Estradiol / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000378:metabolism; D002393:Estrogens, Catechol / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D006894:Hydroxyestrones / Q000096:biosynthesis; D006900:Hydroxylation; D008099:Liver / Q000196:embryology* / Q000378:metabolism; D010902:Pituitary Gland / Q000196:embryology* / Q000378:metabolism
D002393:Estrogens, Catechol; D006894:Hydroxyestrones; C026418:4-hydroxyestrone; D004958:Estradiol; C001390:2-hydroxyestradiol; C014036:4-hydroxyestradiol; C024980:2-hydroxyestrone