AbstractTo determine if Chinese Hamster Ovary (CHO) cells in culture are able to metabolize steroids, CHO cells were incubated in defined medium with 14Cpregnenolone. As shown, 14Cpregnenolone is metabolized to progesterone and other δ53β steroids; this steroidogenic response is appreciably enhanced upon exposure of the cells to 50 nM gonadotropins (human chorionic gonadotropin and follicle‐stimulating hormone). The primary metabolites that accumulate in the medium upon treatment with gonadotropins are 16α‐17β‐dihydroxydehydroepiandrosterone. Exposure of the CHO cells to gonadotropins induces significant increases in the activities of 16α‐hydroxylase, 17α‐hydroxylase, and 17–20 lyase. Similar results are obtained when the CHO cells are treated with 0.1 mM 8‐bromocyclic AMP, indicating that the gonadotropin enhancement of steroid metabolism is a cyclic AMP‐mediated process. CHO cells apparently lack the cholesterol desmolase complex since14C‐cholesterol is not utilized by these cells to produce other steroid metabolites. These results indicate that CHO cells offer an in vitro system for the study of certain aspects of gonadotropin stimula
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