TESTOSTERONE BIOSYNTHESIS IN THE DESERT MOUSE, ACOMYS CAHIRINUS

Abstract

SUMMARY Testosterone synthesis was studied in Acomys cahirinus by incubation of its testis with radioactive substrates. In comparison with other rodents, the Acomys testis was found to have a lower 17β-hydroxysteroid oxidoreductase activity, whereas the activity of 20α-hydroxysteroid oxidoreductase was high. The accumulation of 5-ene-3β-hydroxy metabolites suggested that biosynthesis proceeded preferentially by the 4-ene route. This was confirmed by the simultaneous incubation of [3H]5-ene-3β-hydroxysteroids and [14C]4-en-3-oxosteroids. The predominant route of biosynthesis would, therefore, appear to be: pregnenolone → progesterone → 17α-hydroxyprogesterone → androstenedione → testosterone.