Gonadal sex steroids effects are mediated by slow genomic mechanisms through nuclear receptors as well as by fast nongenomic mechanisms through membrane-associated receptors and signaling cascades. The term sex steroids is nearly always synonymous with sex hormones (Wikipedia). Steroid hormones in mammals regulate diverse physiological functions such as reproduction, mainly by the hypothalamic-pituitary-gonadal axis, blood salt balance, maintenance of secondary sexual characteristics, response to stress, neuronal function and various metabolic processes(fat, muscle, bone mass).