Metabolism of sex hormones in the aortic wall

Estrogen receptors in the adrenal cortex of the possum (Trichosurus vulpecula)

1. Specific [3H]estradiol binding activity with characteristics of estrogen receptors was found in the cytosols and nuclear extracts of the adrenal cortex proper and special zone of the brushtail possum (Trichosurus vulpecula). 2. The specific estradiol receptor had a sedimentation coefficient on sucrose gradients of approximately 9S and a molecular weight on gel filtration of more than 200,000. The adrenal cortex cytosol binds [3H]estradiol with high affinity (Ka 5.5 X 10(9) M-1), and limited capacity (Bmax 62.7 fmol/mg cytosol prot). In competition experiments with different steroids the receptor showed a high affinity for four estrogens and a very low affinity to androgens, progesterone and cortisol. 3. There was no difference in the affinity and maximum binding capacity of the cytosols from cortex proper in male and female animals, but the binding capacity of the special zone of females was half that of cortex proper. Estradiol receptors were found in the kidney, liver, lung, testis and muscle but only in the adrenal and prostate was the binding capacity relatively high compared with the uterus. 4. The specific binding capacity of [3H]estradiol to cytosols of adrenal cortex at different stages of the estrus cycle and pregnancy was unrelated to that of the uterus. In the adrenal the receptor concentration was lowest at estrus, when uterine concentration was high, while in late pregnancy the binding of adrenal cortex and uterus cytosols was almost the same. 5. The possible physiological significance of the presence of a specific estrogen receptor in male and female possums is discussed.

Nuclear uptake of sex steroid hormones in the cardiovascular system of the baboon

Cardiac and arterial tissues of six male and six female adult baboons were examined for nuclear uptake of tritiated 5-alpha-dihydrotestosterone (3H-DHT) or tritiated estradiol-17 beta (3H-E2) by autoradiography. 3H-DHT uptake occurred in nuclei of most atrial and ventricular myocardial fibers, no cardiac interstitial tissues, some arterial endothelial cells, most smooth muscle cells of the intima and inner arterial media, and a few smooth muscle cells of the outer arterial media. 3H-E2 uptake occurred in nuclei of a few atrial and ventricular myocardial fibers, many cardiac interstitial cells, occasional arterial endothelial cells, a few smooth muscle cells of the intima and inner arterial media, smooth muscle cells of the outer arterial media, and nearly all adventitial cells. These observations are consistent with other autoradiographic and biochemical findings which indicate that the heart and major arteries of several mammalian species contain androgen and estrogen receptors in distinctive patterns of distribution among muscle and connective tissue cells.