The Effects of Estradiol, Tamoxifen, and Testosterone on the Weights and Histology of the Epididymis and Accessory Sex Organs of Sexually Immature Rabbits*

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Abstract
The effects of estradiol benzoate (EB), testosterone propionate (TP) and tamoxifen, alone or in combination, on the weight and morphology of the male accessory sex glands were studied in intact and in castrated immature rabbits. TP treatments (2 mg/kg) exerted a stimulatory effect on the glands, resulting in a significant increase in the weight of the epididymis, the proprostate and the prostate of castrated rabbits and of the bulbourethral glands of both intact and castrated rabbits, and in marked morphological changes in all the glands. The epithelium was stimulated but retained its pseudostratified columnar appearance and resembled more the epithelium of normal mature males than that of age matched controls. The bulbourethral glands were the most responsive and the vesicular gland the least responsive to androgen treatment. The response of the glands to EB (25 .mu.g/kg) was characterized by significant weight increases in all the glands of both castrated and intact rabbits, hypertrophy of the musculo-fibrous components and proliferation of the basal layer of the epithelium leading to squamous metaplasia and leukocytic infiltration. Hyperplasia of the fibromuscular stroma was most evident in the cauda epididymis and in the vesicular gland. Squamous metaplasia and leukocytic infiltration were most evident in the ejaculatory duct and in the structures adjacent to it. The antiestrogen, tamoxifen (250 .mu.g/kg), and TP (2 mg/kg) given in conjunction with EB (25 .mu.g/kg) tended to reduce the weight increase caused by estrogen, but the decrease was significant in only a few instances. Tamoxifen (250 .mu.g/kg) administered alone stimulated the epithelium of the accessory sex glands and induced squamous metaplasia, but did not induce hyperplasia of the fibromuscular stroma. Accessory sex glands display a consistent pattern of differential sensitivity to both androgens and estrogens and that these hormones exert their action on different cell types within the organ.