Differential distribution of dihydrotestosterone and estradiol binding sites in the epididymis of the mouse. An autoradiographic study

Sites of aromatization of [3H]testosterone in forebrain of male, female and androgen receptor-deficient Tfm mice: an autoradiographic study

The distribution of radioactivity after injection of [3H]testosterone was studied in the forebrain of adult mice by thaw-mount autoradiography. Nuclear labeling was high in neurons in the dorsal part of the medial nucleus of the amygdala and in the dorsocaudal part of the bed nucleus of the stria terminalis. Low nuclear uptake occurred in the medial preoptic nucleus, in mediobasal hypothalamic nuclei and in the ventromedial amygdala. Nuclear concentration of radioactivity was not influenced by competition with dihydrotestosterone and was present in androgen receptor deficient Tfm mice. It was totally abolished by competition with estradiol. This indicates that in the brain [3H]testosterone is converted to estrogenic metabolites which bind to estrogen receptors. Nuclear labeling after [3H]testosterone was restricted to a few of the brain nuclei, known to contain estrogen receptors indicating that aromatization occurs only in select regions. The results suggest that testosterone acts on the brain via estrogen receptors.

Differential distribution of 3H dihydrotestosterone and 3H estradiol nuclear binding sites in mouse male accessory sex organs. An autoradiographic study

The distribution of specific nuclear binding sites for androgens and estrogens in the male accessory sex organs of the mouse was assessed by autoradiography with 3H dihydrotestosterone (3H DHT) and 3H estradiol (3H E2). With 3H DHT nuclear labeling differed among the epithelia of the organs. It was high in seminal vesicle and ampullary gland, moderate in ventral prostate, urethral gland, prostatic excretory ducts and the ampulla ductus deferentis, low in dorsal prostate and low or absent in coagulation gland. With 3H E2, in contrast, epithelial nuclear labeling was high only in coagulation gland, moderate or low in seminal vesicle, low or absent in ventral and dorsal prostate and absent in ampullary gland and ampulla ductus deferentis. In the lamina propria of all organs nuclear labeling with 3H DHT was generally moderate and existed only in some cells, with the highest number in the ampulla ductus deferentis. With 3H E2, nuclear labeling in the lamina propria showed a high intensity in all organs, except in ventral and dorsal prostate which remained unlabeled. Many labeled cells were found in the deferent duct and its ampulla, while in the other organs only a few cells showed nuclear labeling with 3H E2. In the smooth muscle sheath of all organs, some muscle cells were moderately labeled with 3H DHT, but not with 3H E2. The results indicate the presence of nuclear receptors in male accessory sex organs for both dihydrotestosterone and estradiol. The differential patterns of 3H DHT and 3H E2 nuclear uptake suggest differential sensitivities of the individual organs and their tissue compartments for androgens and estrogens.