The effects of lead on the male rat reproductive system.

Lead acetate was administered to male rats for 9 weeks in doses of 0.3, 33 or 300 mg/kg daily by gavage. The lowest dose significantly reduced the number of sperm in the cauda epididymis and the highest dose increased the proportion of abnormal sperm in the cauda. There was no significant effect on the number of each type of testicular germ cell. The highest dose of lead reduced the rate of incorporation of lysine into protein significantly in the liver but not in the testes. The highest dose also reduced body weight gain significantly. The surprisingly slight effect of lead on the germinal tissue may be due to a protective effect of the blood-testes barrier.