LH receptor in testosterone-producing ovarian tumor. In vivo and in vitro HCG-stimulated testosterone production.

The aim of the present work is to report in vivo and in vitro hormonal studies performed on a 71 year old virilized woman due to a Leydig cell tumor of the ovary. Testosterone (T), Cortisol, DHEA(s) and ACTH concentrations were determined in blood samples taken every 4 h throughout 24 h previous to surgery. T average concentration from the 6 samples was 3.3 ng/ml (range: 2.5-4.2 ng/ml). DHEA(s) was normal; Cortisol and ACTH levels were normal and their circadian rhythms were present. T value obtained during Dexamethasone administration (2 mg daily/3 days) was 2.4 ng/ml. This value was significantly higher than those obtained from postcorticoid normal women (0.3 +/- 0.1 ng/ml), suggesting an extraadrenal source. T concentration was 5.4, 6.0 and 6.6 ng/ml at 24, 48 and 72 h after hCG injection (5000 IU). After tumor removal, T values decreased progressively up to 6.0 ng/ml values, 5 days later, and remained steady on the following days. The studies performed in vitro were: determination of T in the tumor cytosol, specific binding of LH to ovarian tumor cell membrane fraction and T production in tissue culture in both with and without added hCG conditions. Normal ovarian tissue from the same patient under similar experimental conditions was used as control. The T concentration expressed as ng/mg of protein in the tumor and normal ovarian cytosol was 9.1 and 1.1, respectively. Scatchard analysis of specific 125I-hCG binding to tumor and normal ovarian cells indicated 53 pg and 28 pg of labeled hCG bound/mg of membrane protein, respectively, suggesting that this Leydig cell tumor of the ovary contained LH (hCG) receptors. The amounts of T, expressed as ng/mg of tissue/6 days, generated by tumoral and normal tissue ere 4.1 and 0.3, respectively. The addition of hCG elicited a response of 6.3 and 0.6 ng/mg protein/6 days in both preparation, respectively. These results demonstrate in vivo and in vitro hCG-stimulated T production in this particularly masculinizing ovarian tumor and suggest tumoral LH dependence.