Factors Regulating the Metabolism of Steroids

Neonatal Differentiation of Hepatic DHA 16α- and 7α-Hydroxylases

“…The greater specific activity of the dehydroepiandrosterone (DHA)1 2 * * 16u-hydroxylase in liver slices of adult males in comparison to females and its diminution after orchiectomy were reported by Colas [3]. This NADPH- 1 The following abbreviations are used: dehydroepiandrosterone, DHA (3(3-hydroxyandrost-5-en-17-one); 16a-OH-DHA (3|3,16a-dihydroxyandrost-5-cn-17-one); 7a-OH-DHA (3|3,7a-dihydroxyandrost-5-en-17-one); A5-diol (androst-5-ene-3p,17(3-diol).…”

“…Major differences in the metabolic pathways of male or female rat liver have been described for various steroids and drug substrates [1,2]. The greater specific activity of the dehydroepiandrosterone (DHA)1 2 * * 16u-hydroxylase in liver slices of adult males in comparison to females and its diminution after orchiectomy were reported by Colas [3].…”

Differentiation of Steroid Metabolism in the Rat and Mechanisms of Neonatal Androgen Action

“…Reviews (15,69) of the earlier literature indicate that the reductive as well as the oxidative metabolism is sex-dependent and that it involves many different enzymes. Considering only the reductive metabolism of the steroid A4-3-keto-and 20-keto group, the male is characterized by a low 5a-reductase and 3a-hydroxysteroid oxidoreductase activity but a high 3(3-hydroxysteroid and 20/3-hydroxysteroid oxidoreductase activity.…”

“…Peripheral metabolism must be considered as an important controller of hormone levels. It is well known that in rats this metabolism is different in the two sexes (15,69). The sex difference appears at the onset of puberty.…”

In vitro effects of oestrogen on 5α reduction of testosterone in hormone-dependent rat mammary carcinomata

“…In vitro addition of oestradiol reduces tumour synthesis of 5ac-reduced metabolites from testosterone, particularly 5ac androstanediol. Although this is the first report that oestrogen may affect the production of 5a-reduced steroids by mammary cancers, it is well documented that 5ac-reduction may be hormonally controlled in other tissues such as liver (Schriefers, 1967), adrenal cortex (Kitay, Coyne and Swygert, 1970) and prostate (Farnsworth, 1972). In common with the results presented in this study for mammary tissue, oestradiol inhibits 5ac-reduction in both adrenal cortex and prostate.…”