Treatment of cyclic and pregnant rats with progesterone stimulates cell proliferation within the islets of Langerhans. It was investigated whether this effect of progesterone depends on sex and/or the presence of the gonads or the presence of oestradiol. For this purpose, Silastic tubes containing progesterone were inserted s.c. in intact and gonadectomized male and female rats, and in gonadect...

Male mice that are pttg-null develop sexually dimorphic diabetes with hypoinsulinemia secondary to reduced postnatal-cell proliferation and an inability to expand islet cell mass with aging. We therefore examined the effects of sex-steroid manipulation on diabetes development in pttg-/- male mice. Surgical gonadectomy was followed by implantation of 90-day slow-release pellets releasing 17beta-...

Down-regulation of microsomal androgen-dependent CYP2C1 1 is produced in male rat liver by dietary vitamin A deficiency. Decreased circulating androgen concentrations also occur in vitamin A-deficient male rats. Both effects are prevented by addition of all-trans-retinoic acid to the diet. The present study evaluated directly whether androgen deficiency may be responsible for the down-regulatio...

The decline in testosterone levels in men during normal aging increases risks of dysfunction and disease in androgen-responsive tissues, including brain. The use of testosterone therapy has the potential to increase the risks for developing prostate cancer and or accelerating its progression. To overcome this limitation, novel compounds termed "selective androgen receptor modulators" (SARMs) ha...

Gonadectomy is widely used to treat and prevent behavior problems including the aggressive behavior of dogs. The aim of this study was to determine whether aggressive behavior toward familiar people, strangers, or other dogs was significantly different in dogs gonadectomized at various ages vs. intact dogs using the Canine Behavioral Assessment Research Questionnaire (C-BARQ) with multivariate ...

The aim of the present study was to evaluate sex differences in tumorigenesis by assessing the number of Ki-67-positive cells [Ki-67(+)] in urethane-induced mice lung tumors and the effect of sodium valproate (NaVP) in BALB/c mice. Gonad-intact and gonadectomized female and male mice were divided into the following groups: i) Treated with urethane, ii) treated with urethane and NaVP and iii) go...

Introduction: Sex differences in outcomes of Spinal Cord Injury (SCI) suggest a sex-hormone-mediated effect on post-SCI pathological events, including glutamate excitotoxicity. This study aimed to investigate the importance of gonadal hormones on glutamate release subsequent to SCI in rats. Methods: After laminectomy at T8-T9, an electrolytic lesion was applied to the spinothalamic tracts of m...

This study investigated the importance of the male sex hormone testosterone on salt-induced hypertension, renal alpha(2)-adrenoceptor subtype distribution, and gene expression in salt-sensitive (SBH) male Sabra rats. Comparisons of blood pressure and renal alpha(2)-adrenoceptor subtype gene expression and receptor densities have been made among sham-operated rats, and gonadectomized rats treate...

Some effects of perinatal hypoxia on pulmonary circulation are permanent. Since pulmonary vascular sensitivity to hypoxia in adults differs between sexes, we hypothesized that gender-based variability also exists in the long-term effects of perinatal hypoxia. Rats spent 1 wk before and 1 wk after birth in hypoxia (12% O2) and then lived in normoxia. When adult, females, but not males, with the ...