Reproductive toxicity of chronic lead exposure in male and female mice

The reproductive toxicity of lead was investigated in NMRI mice exposed to 0.5% lead acetate in drinking water from day 1 of intra-uterine life until 60 days after birth. Compared with control mice, the weights of lead- exposed fetuses and subsequently of the lead-exposed weaned pups, male and female, diminished by 11 and 13% respectively. The lead-exposed male and female offspring of lead-exposed dams were mated with unexposed females and males, to examine the effect of lead exposure on reproductive function. Male fertility was not affected but reduced female fertility was observed: litters were smaller and a smaller number of implantation sites was found in lead-exposed females. In lead-exposed males, the weights of the body, testes and epididymes diminished by about 13%, and seminal vesicle and ventral prostate weights, by about 29%. Testicular histology and the number and mor phology of epididymal spermatozoa were normal. The lev els of plasma FSH, LH and testosterone, and of testicular testosterone, were not modified. These results suggest that the hypothalamic-pituitary-testicular axis is not adverse ly affected by the above lead exposure, and that therefore the decreased seminal vesicle and ventral prostate weights might not be the consequence of reduced testosterone lev els. The hypothesis that lead has a direct effect on these organs as well as a secondary effect resulting from possi bly reduced food consumption by lead-exposed mice can not be excluded. Consequently, in male NMRI mice, expo sure to lead might affect reproductive function by acting directly and/or indirectly on accessory sex organs.