Binding studies of H-Y antigen in rat tissues: indications for a gonad-specific receptor.

The binding capacity for H-Y antigen was studied in various rat tissues of both sexes. In nongonadal tissues (liver, kidney, brain, epidermis) binding could not be demonstrated. In contrast, the gonads are able to bind exogenously supplied H-Y antigen. In the ovary, the binding capacity remains unchanged in newborn and adult animals, while in the testis, this capacity decreases with age. A receptor like that of a proteohormone is assumed to exist in the gonads but not in other tissues. In nongonadal tissues, H-Y antigen apparently is present only if the cell itself synthesizes the antigen. The H-Y antigen receptor of the gonads is not sex-specific. Thus, the primary sex differentiation depends on whether H-Y antigen is synthesized in the organism.