Studies on Interstitial Cells in Tissue Culture: Steroid Biosynthesis in Monolayers of Mouse Testicular Interstitial Cells1

A cell culture in monolaycr, derived from a mouse testicular interstitial cell tumor of spontaneous origin, persistently produces steroids de novo. The major products are progesterone2 and its reduced derivative, 20αhydroxy-4-pregnen-3-one. The latter accumulates to a concentration as high as 7 μg/ml of culture medium in 4 days. Exogenous pregne:iolone or progesterone is readily converted to this steroid within hours. Added 3′,5 ′-cyclic AMP at A very low concentration (5×10−6M) significantly {stimulates steroidogenesis, a maximal 3-fold increase being obtained at 10−4M. Both TPNH and DPNH at 10−3M also cause 3-fold stimulation in steroid secretion. Cycloheximide (10 ppm) inhibits such stimulation by added factors completely. So far, no trophic hormones have been found to elicit similar effects from the culture. The cultured cells are near-diploid and have a generation time of approximately 3.5 days in the exponential phase of growth. A clonal line retains these functional characteristics after over 14 months in continuous serial culture. {Endocrinology81: 440, 1967)