Studies on the 5 alpha-androstane-3 beta,17 beta-diol-6 alpha-hydroxylase and on the 5 alpha-androstane-3 beta,17 beta-diol-7 alpha-hydroxylase in anterior hypophysis of male rats.

In anterior pituitaries from male rats, it appeared that 5 alpha-androstane-3 beta,17 beta-diol was quickly metabolized into 5 alpha-androstane-3 beta,6 alpha-17 beta-triol and 5 alpha-androstane-3 beta,7 alpha,17 beta-triol by action of 6 alpha- and 7 alpha-hydroxylases. Hydroxysteroid hydroxylases were located in endoplasmic reticulum and were dependent on NADPH+. Their optimum pH was 8.0, optima temperature, 37 degrees C, and their apparent Km was 2.7 microM. Hydroxylative reactions were not reversible and not modified by gonadectomy. Hydroxylation seemed an efficient control of the pituitary level of 5 alpha-androstane-3 beta,17 beta-diol.