Ontogeny of steroid metabolizing enzymes in rat oligodendrocytes

Abstract Rat oligodendroglial cells were isolated from newborn and developing brains and used immediately after, for quantification of steroid metabolizing activities. Oligodendrocytes (Ol) and their progenitor cells were incubated with [ 14 C] testosterone, [ 14 C] progesterone, [ 14 C] pregnenolone or [ 14 C] dehydroepiandrosterone (DHEA). Oligodendrocytes and their progenitor cells expressed different steroid metabolizing enzymes. The main activities were 5α reduction of testosterone and progesterone and 3β hydroxy steroid dehydrogenase–isomerase which transformed pregnenolone into progesterone and DHEA into Δ4 androstenedione. 5α reductase activity increased in male and female rats in parallel with testosterone or progesterone. Contrary to this, 3β hydroxysteroid dehydrogenase-isomerase activity was found to be high in the young rat and to decrease when testosterone and progesterone plasma concentration increased.