Enzyme induction in Streptomyces hydrogenans. Comparison of the effects of different steroids to increase the activity of 3α, 20β‐hydroxysteroid dehydrogenase and of 3β, 17β‐hydroxysteroid dehydrogenase

Abstract After cultivation of Streptomyces hydrogenans in the presence of different steroids the activity of both 3α,20β‐hydroxysteroid dehydrogenase and 3β, 17β‐hydroxysteroid dehydrogenase was determined in the cell homogenate of the microorganism. By comparing the efficacy of the steroids to increase enzyme activities, steroids could be divided into 3 groups: a) steroids which stimulated preferentially the activity of 3α,20β‐hydroxysteroid dehydrogenase (e. g., corticosterone), b) steroids which stimulated preferentially 3β,17β‐hydroxysteroid dehydrogenase (estradiol‐17β), and c) those behaving intermediately (e. g., progesterone, 5α‐dihydrotestosterone). Highest 3β, 17β‐hydroxysteroid dehydrogenase activity could be measured 2 h after addition of 5α‐dihydrotestosterone to the culture medium. The activity of 3α, 20β‐hydroxysteroid dehydrogenase, however, increased continuously up to 4 h. 3α,20β‐hydroxysteroid dehydrogenase and 3β,17β‐hydroxysteroid dehydrogenase syntheses seemed to be controlled by steroids in a non‐coordinate manner.