[Physiologic mechanisms of the reaction of the reproductive system in female rats to chronic exposure to low doses of toluene].

Chronic inhalation of toluol (2-4 months) did not affect the menstrual cycle in female rats but distorted the mechanisms of the reproduction control. The level of gonadoliberin decreased during dioestrus in preoptic area, the correlation between concentrations of luteinizing and folliculo-stimulating hormones became disordered, and the prolactin secretion increased. Preovular peaks of gonadotropins secretion became lower in proestrus. The cold stress increases the prolactin secretion and decreases the gonadoliberin content in the hypothalamus of control animals. These events do not happen after toluol inhalation. After 4 months of toluol inhalation, the levels of estradiol and progesterone decrease in the blood. However, normal response to gonadotropic stimulation is preserved which suggests a secondary character of hormonal disorders, in response to primary disturbances in the hypothalamo-hypophyseal link of the reproduction control.