Men have higher blood pressure than women, and androgens and oxidative stress have been implicated as playing roles in this sexual dimorphism. The spontaneously hypertensive rat (SHR) is an animal model of both androgen- and oxidative stress-mediated hypertension. Therefore, the present studies were performed to test the hypothesis that androgens cause hypertension in SHR in part by stimulating...

The central component of the medial preoptic nucleus (MPNc) of the rat has served as an excellent model of sexual differentiation. The MPNc is larger in adult males than in females, and its development is regulated by perinatal gonadal hormones. Although testosterone (T) and its metabolite estradiol (E) sexually differentiate this region, the exact mechanism by which they act during development...

The relationship between polyamine synthesis, growth and secretion in vivo was examined in ventral prostates from: (a) intact rats aged 3-60 weeks; (b) animals castrated for 7 days before injection with 5r-dihydrotestosterone (17,8-hydroxy-5a-androstan-3-one), testosterone and 5 r-androstane-3,8,17,f-diol for up to 10 days; (c) rats injected with the 3fi,17fidiol immediately after castration. O...

Hormonal effects of Tribulus terrestris (TT) were evaluated in primates, rabbit and rat to identify its usefulness in the management of erectile dysfunction (ED). TT extract was administered intravenously, as a bolus dose of 7.5, 15 and 30 mg/kg, in primates for acute study. Rabbits and normal rats were treated with 2.5, 5 and 10mg/kg of TT extract orally for 8 weeks, for chronic study. In addi...

Increased levels of androgens in postmenopausal women are considered to be a risk factor for breast cancer. Testosterone, alone or in combination with estrogen, induces epithelial dysplasia and mammary tumors in Noble rats. Since this model of hormone-induced neoplasia has not been reported in other rat strains, we studied the effect of testosterone on the mammary gland morphology of female Wis...

Depigmentation of hair shafts is a hallmark human aging. However, it remains unclear how aging causes to grey. Here, we found that single session plucking via waxing grey in castrated mice. Moreover, this greying continued for several cycles. Given androgen secretion decreases with age both male and female humans, the present result suggests decrease may contribute age-related greying. I...

Prostatic hyperplasia can be induced in both intact and castrated dogs and in intact cynomolgus monkeys by the administration of androgenic steroids. Estrogenic steroids potentiate this effect in dogs. These changes also can be induced by androstenedione, which increases androgen and estrogen levels. Atamestane (ATA; 1-methyl-3,17-dione-androsta-1,4-diene), a potent aromatase inhibitor, inhibit...

Gonadotropin-releasing hormone (GnRH) receptor antagonists have potential in treating numerous hormone-dependent pathologies including cancers of the prostate, breast, and ovary, endometriosis, and fertility disorders. An unmet clinical need exists for an orally available GnRH receptor antagonist. Guided by structure-activity relationships, ligand-based targeted library designs, and biomarker m...

Estrogen 2- and 4-hydroxylase (ESH), a microsomal enzyme which mediates the formation of catechol estrogens, has been studied in the kidneys of castrated male Syrian hamsters, a species uniquely susceptible to induction of renal carcinomas by both steroidal and stilbene estrogens. The apparent Km for estrone was 17.0 microM, and Vmax was 0.5 pmol per mg protein per min for ESH in renal microsom...

CRITCHLOW, V., R. A. LIEBELT, M. BAR-SELA, W. MOUNTCASTLE, AND H. S. LIPSCOMB. Sex dijerence in resting pituitaryadrenal function in the rat. Am. J. Physiol. 205(5): 807-815. I g63.-Resting levels of plasma and adrenal corticosteroids, pituitary content of adrenocorticotropin, and circulating leukocytes were determined at intervals during controlled 24-hr light-dark cycles in intact, castrated,...