Effect of cyproterone acetate and conjugated estrogens on the human insulin receptor

It has recently been reported that prednisone increases whereas dexamethasone and cortisone decrease insulin binding to monocytes, thus suggesting that different steroids may exert opposite effects on the insulin receptor, depending on their chemical structure. In order to gain further insight into the modulations of the insulin receptor by other steroids, the effect in male patients of short‐ and long‐term oral treatment with cyproterone acetate (100–150 mg/day) or conjugated estrogens (20 mg/day) was evaluated. Cyproterone acetate did not produce any statistical, evident change in insulin binding to monocytes after either short‐term (5 days) or long‐term (1 year) treatment. Short‐term (5 days) administration of conjugated estrogens did not affect insulin binding; however, long‐term (1 year) treatment produced a highly significant decrease in insulin binding due mainly to changes in receptor concentration. Thus, cyproterone acetate does not affect the insulin receptor, whereas conjugated estrogens reduce insulin receptors after long‐term treatment, as with dexamethasone and cortisone. Estrogens probably play a role in the insulin binding impairment which occurs during the luteal phase of the menstrual cycle as well as in users of the “pill”.