Androgen induction of a specific uterine protein

Studies were conducted to determine the ability of androgens in vitro to elicit the induction of a specific uterine protein (IP) normally attributed to estrogens. Both 5alpha-dihydrotestosterone (5alpha-DHT) and testosterone were effective in stimulating IP synthesis in rat uterine tissue in a concentration dependent manner (0.1 muM to 50 muM). 5alpha-DHT was more effective than testosterone and reached approximately 85% of the estradiol stimulated IP response at 10 muM and 50 muM; whereas testosterone was only able to achieve about a 70% IP response at 50 muM. This androgen stimulated IP synthesis was stereospecific since cis-testosterone and 5beta-DHT, inactive androgen isomers, were unable to evoke a detectable IP response at any concentration studied. Antiandrogens were unable to inhibit the 5alpha-DHT stimulated IP synthesis but antiestrogens were able to greatly inhibit the 5alpha-DHT and testosterone stimulated IP responses in a concentration dependent manner. The anti-estrogens, themselves, were very weak inducers of the IP response. The nuclear accumulation of the estrogen receptor by various androgens and inactive androgen isomers was also determined. Approximately 100% nuclear accumulation of receptor was attained with 1 muM 5alpha-DHT, whereas 50 muM testosterone was needed for 100% uptake. 5beta-DHT was unable to translocate the receptor at the lower concentrations tested, but caused a significant nuclear accumulation of 50 muM. Cis-testosterone was unable to cause the nuclear accumulation of the estrogen receptor at all concentrations studied. These studies suggest that some of the estrogen receptors accumulated in the nuclei by androgens, inactive androgen isomers, or antiestrogens may not be capable of eliciting a biological response.