Neurosteroids: steroidogenesis in primary cultures of rat glial cells after release of aminoglutethimide blockade.

Newborn rat glial cells were established in primary culture for greater than or equal to 3 weeks under conditions previously reported to permit differentiation of cholesterol side-chain cleavage activity. The cells were incubated for 48h with 3-H-Mevalonolactone in presence of Mevinolin (avoiding isotopic dilution of endogenous origin) and aminoglutethimide, a blocker of cholesterol side-chain cleavage. Radioactive steroid synthesis was then allowed to proceed in absence of aminoglutethimide, for 16h in presence of Trilostane, an inhibitor of 3 beta-hydroxysteroid dehydrogenase precluding formation of delta 4-3-ketosteroids. 3H-cholesterol accounted for approximately 10 percent of the radioactivity in cell extracts. 3H-delta 5-pregnene-3 beta, 20 alpha-diol (20-OH P) was the major steroid produced and was released in the culture medium. Dexamethasone (10 nM) increased 20-OH P formation by 30 percent, whereas cellular 3H-cholesterol decreased more than expected from the augmented formation of 20-OH P.