Effect of aeration on cortisol and androgen output by pig adrenal homogenate

Of the steroids produced by pig adrenal homogenate, the output of cortisol+11-deoxycortisol, corticosterone, 11 beta-hydroxyandrostenedione, and the steroid intermediates: pregnenolone, 17 alpha-hydroxypregnenolone, progesterone, 17 alpha-hydroxyprogesterone were analysed. The incubations were carried out with and without aeration. Without aeration the oxygen tension in assay medium decreased during incubation in spite of constant shaking. However, it remained constant (140 Hgmm) with aeration throughout the incubation (60 min). The results of steroid analysis demonstrated that the output of 11 beta-hydroxyandrostenedione decreased strongly, and that of cortisol slightly without aeration, however, the output of corticosterone did not change. The addition of 17 alpha-hydroxypregnenolone or 17 alpha-hydroxyprogesterone to the incubation medium eliminated the decrease in the output of cortisol, but not that of 11 beta-hydroxyandrostenedione. The observations suggest that the activation of oxygen in the enzyme reaction catalyzed by 17, 20-lyase, and perhaps by 17 alpha-hydroxylase is weaker than the activation mediated by 21-hydroxylase and 11 beta-hydroxylase.