Increased estrogen formation and aromatase activity in fibroblasts cultured from the skin of chickens with the Henny feathering trait.

Abstract

The henny feathering trait in chickens leads to a marked increase in the conversion of androgen to estrogen in skin and other peripheral tissues with the result that feathers of affected males are feminized. To gain insight into the mechanisms responsible for this increased estrogen synthesis, we studied the conversion of testosterone to estrogen in fibroblasts cultured from the skin of control chickens and from two breeds carrying the henny feathering trait, the Sebright bantam and the Campine. Estrogen synthesis was measured in suspensions of intact fibroblasts and in cell-free fibroblast extracts by two assays: 1) direct measurement of 17 beta-estradiol formation from [1,2,6,7-3H]testosterone, and 2) assessment of 3H2O release from [1 beta-3H]testosterone. Both assays gave comparable results. Estrogen formation was as much as several hundred-fold higher in fibroblasts cultured from skin of chickens carrying the henny feathering trait compared to that observed in fibroblasts from skin of control chickens. The current data indicate that increased estrogen formation in skin of chickens with the henny feathering trait is due to an enhanced activity of the aromatase complex of enzymes responsible for estrogen synthesis. The molecular basis for this increased activity is unclear.