Autoradiographic demonstration of binding sites for oestradiol and dihydrotestosterone in the urinary tract of male and female baboons

By light microscopic atuoradiography, the kidneys, ureters and urinary bladder of male and female baboons were examined in an effort to define which cells in these three organs were targets for oestradiol (E₂) and dihydrotestosterone (DHT). In the parenchyma of the kidney, there was no specific uptake of either ³H-E₂ or ³H-DHT, whereas the cortical and medullary connective tissue cells sequestered only ³H-E₂. The latter hormone was also found in cells comprising the tunica intima and tunica media of the renal, interlobar and arcuate arteries. The two radiolabelled steroids were concentrated in connective tissue cells of the lamina propria of the ureter and bladder and in the tissue adjacent to smooth muscle fasciculi. Only ³H-DHT was retained by the smooth muscle in these two organs. These observations indicate that specific steroid binding sites are present in the urinary system of the baboon. Their role in the physiology of the kidney, ureter and urinary bladder remains at this point unclear.