The estrogen receptor-alpha (ERalpha) knockout mouse (alphaERKO) lacks ERalpha throughout development; therefore, an adult model for the study of estrogen effects in male mice was recently developed using the antiestrogen ICI 182,780. However, differences between species have been noted during immunostaining for ERalpha in the male tract as well as in response to treatments with antiestrogens. ...

Methyl(acetoxymethyl)nitrosamine (DMN-OAc) when in jected i.p. in Sprague-Dawley Charles River CD rats selectively induces epithelial tumors of the intestines. Males are more severely affected than females. To determine whether the strain of rat determines the quantity or type of tumors induced, 5week-old male and female rats of Sprague-Dawley (SD), Buffalo (BUF) and Fischer (F344) strains were...

  Objective(s): The effect of maternal voluntary exercise on hippocampal BDNF level in rat offspring was studied. In addition, the possible role of hippocampal BDNF receptors in maternal exercise induced enhancement of learning in the rat pups was investigated.   Materials and Methods: Pregnant rats have been randomly assigned to sedentary control or voluntary exercise groups. Each of the exerc...

Sexual behavior in many mammals is characterized by its dependence on circulating titer of sex hormones and sexual dimorphism. Sexual dimorphism in female and male behavior depends, not on genetic sex but on early actions of sex hormone at a specific period during ontogenesis in each species. The period, termed the critical period for the brain sex differentiation, spans over gestational day 18...

At birth testicular androgens irreversibly program brain centers involved in hypothalamopituitary control of hepatic sex-dependent steroid and drug metabolism. This imprinting process results in activation of a hypothalamic "feminostatin"-a secreting center that is turned on just before puberty. Feminostatin inhibits pituitary secretion of "feminizing factor," a pituitary hormone that feminizes...