Estrogen accumulation by porcine granulosa cells in culture

Porcine granulosa cells in culture specifically concentrate ³H-labeled estrogens. Estrone (E₁) uptake was greater than 17β estradiol (E₂) uptake, and was maximal within 15 minutes at 37°C. Nonspecific uptake of ³H-E₁ and ³H-E₂ in the presence of a 1000-fold excess of the homologous unlabeled steroid was 21.4 to 37.5% for E₁ and 47.9% for E₂. Estriol, 17α E₂, 17β E₂ and testosterone competed actively with E₁ for concentration by the granulosa cells. Treatment of the cultured cells with chorionic gonadotropin (hCG) did not increase E₁ uptake over untreated controls when compared on the basis of cell DNA. However, when compared on the basis of cell protein, hCG caused a significant increase in E₁ uptake on day 4 of treatment. These studies provide further evidence that the porcine granulosa cell is a target cell for the action of estrogens.