THE EFFECT OF ARTIFICIAL CRYPTORCHIDISM ON SERUM OESTROGEN AND TESTOSTERONE LEVELS IN THE ADULT MALE RAT
ABSTRACT Oestrone, oestradiol and testosterone levels were measured by radioimmunoassay in male rats 0.5, 1, 4, 8 and 16 days after rats were either made artificially cryptorchid or sham-operated. Oestradiol levels were not significantly different between cryptorchid and control rats 12 h or 1 day after surgery, but levels in cryptorchid animals fell to 35 % of controls on day 4 (P < 0.05), 31% on day 8, and 29% on day 16 (P < 0.01). Conversely, oestrone and the total of the two oestrogens was higher in cryptorchid rats at one-half day (P <0.05), but did not differ at any other time. Testosterone levels were generally lower in cryptorchid rats than in controls. The minor contribution of oestradiol to total oestrogen levels and the lack of change of total oestrogens in cryptorchid rats led to the conclusion that oestrogens are probably not the tubular regulator of FSH in the male.