INDUCTION OF TARGET ORGAN INSENSITIVITY TO TESTOSTERONE IN THE MALE GUINEA-PIG WITH CYPROTERONE

Abstract

SUMMARY Male guinea-pigs born to females injected with cyproterone acetate (CA) from day 28 to 58 of gestation developed non-tubular hypospadiac penes and stunted seminal vesicles and prostate glands. When adult animals were stimulated with exogenous or endogenous androgens, secretory failure and only minimal growth was observed in the accessory organs. The concentrations of endogenous testosterone in systemic plasma from intact CA males were not different from those in control males, but the uptake and distribution of [1,2-3H]testosterone in castrated CA males did not conform to control values. Deficiences in mounting, intromission and ejaculatory patterns were observed in CA males compared with controls. Lordosis, the primary behavioural response used as a criterion of 'feminization', was never observed in CA males even when large concentrations of oestrogens were administered. The results suggest that target organ insensitivity to testosterone in adulthood can be the result of deficient androgenic stimulation during embryological differentiation.