Characteristics of the calf uterine androgen receptor

Immunohistochemical localization of androgen and progesterone receptors in the uterus of the camel (Camelus dromedarius)

Ten adult, cyclic female camels (Camelus dromedarius) were used to describe the distribution of androgen (AR) and progesterone (PR) receptors in the uterus using immunohistochemistry. Both AR and PR were distributed throughout the different compartments of the uterus with nuclear staining for AR and PR seen in the cells of epithelia (luminal and glandular), stroma and myometrial smooth muscles. AR immunostaining was not uniform in distribution and intensity; the surface epithelium and the glandular epithelium in the adluminal region of the endometrium showed lower AR immunoreactivity than other compartments of the uterus. PR immunostaining showed uniformity in both distribution and intensity strong PR immunostaining intensity in almost all cells of the different uterine compartments. The intensity and distribution of PR immunostaining in epithelia of lumen and glands in the adluminal regions of endometrium was higher (P<0.05) than that of AR. In conclusion, immunohistochemical localization of AR and PR in the uterus of the cyclic dromedary camel indicates the important roles of androgen and progesterone in controlling the uterine activity during the follicular phase.

Androgen regulation of the insulin-like growth factor-I and the estrogen receptor in rat uterus and liver

For the first time testosterone is shown to be an important regulator of the insulin-like growth factor-I (IGF-I) in the rat uterus under in vivo conditions. In this study the regulation of IGF-I and the estrogen receptor (ER) by gonadal steroids in the uterus and liver of female rats was monitored. The ER level was assayed by hormone binding after treatment with testosterone, 5 alpha-dihydrotestosterone or estradiol and specific mRNA species were analyzed by a solution hybridization/RNase protection assay using 35S-labeled RNA probes. Ovariectomized rats restored uterine weight after treatment with testosterone. Uterine IGF-I mRNA was more than 20-fold higher in testosterone treated rats compared to untreated ovariectomized controls after 48 h treatment. The effects of testosterone on ovariectomized animals was followed in a timecourse study. Testosterone administration increased uterine IGF-I mRNA expression during the first 48 h and the maximally induced level was maintained throughout the duration of the experiment (168 h). Since induction of IGF-I mRNA by estrogen is transient, these data indicate that androgen and estrogen increase IGF-I mRNA by different mechanisms. Regulation of IGF-I mRNA by gonadal steroids was also studied in hypophysectomized animals. The rats were given either testosterone, 5 alpha-dihydrotestosterone or estradiol, and uterine IGF-I mRNA was measured after 1 week of treatment. At this timepoint estrogen treated rats showed levels of IGF-I mRNA not significantly different from those of hypophysectomized controls. In contrast testosterone and 5 alpha-dihydrotestosterone increased the IGF-I mRNA level 30 and 40 times, respectively, relative to hypophysectomized control animals. Since 5 alpha-dihydrotestosterone is not convertable to estrogen, the induction by testosterone was considered to be a true androgenic phenomenon.