Experimental study of mechanisms of disturbances of hypothalamic regulation of reproduction

Summary: Diurnal rhythms of the activity of a number of monoaminergic systems of the hypothalamus (norepinephrine and serotonin in PA and ME-ArN, as well as dopamine in ME-ArN) have been shown to depend on the functioning of an endogenous circadian oscillator in SCN of the hypothalamus. Light modifies the diurnal rhythms of the neurotransmitters. Enhancement of the activity of the noradrenergic systems with sex steroids in proestrus is an important mechanism of the forming of the preovulatory surge of GnRH and gonadotropines’ secretion, which initiates ovulation. Consideration of our own experimental data and literature allow the supposition that the change of diurnal rhythms of norepinephrine in PA and ME-ArN could result in profound disturbances of hypothalamic regulation of reproductive cycles and be one of key reasons for negative effect of xenobiotics on reproduction. Supported by RFBR grant 04-04-49204.