Saturnism in the male rat: endocrine effects

The effect of exposure to lead on endocrine function was studied in pubertal rats treated with 1.0 g/l lead acetate (PbAc) in drinking water for 20 days (subacute group) or 9 months (chronic group) in addition to iv injections of PbAc (0.1 mg/100 g body weight) every 10 (subacute group) or 15 days (chronic group). Although basal levels of testosterone were higher both in the plasma and in the testes of acutely intoxicated animals, the circulating levels of luteinizing hormone (LH) were not affected in either group, nor was the LHRH content of the median eminence. The density of [125I]LH/hCG binding sites in testicular homogenates was reduced by saturnism in both groups. However, the apparent affinity constant of the hormone-receptor complex significantly increased. These data can be viewed as the result of a mixture of specific lead toxicity (e.g., at the enzyme level) with other more general actions (e.g., at the level of the hypothalamus-pituitary-testicular axis).