CHRONIC LEAD-EXPOSURE EFFECTS IN THE CYNOMOLGUS MONKEY (MACACA-FASCICULARIS) TESTIS

Although reproductive consequences of high circulating blood lead leve ls (greater than or equal to 60 mu g/dL) have been reported, potential adverse effects of chronic lead exposure in males that result in low to moderate blood lead levels (10-25 and 26-60 mu g/dL, respectively) are unknown. Effects of chronic lead exposure to testis ultrastructure were determined in the cynomolgus monkey after oral administration of lead acetate (1500 mu g/kg BW/day) in a vehicle in the following grou ps: from birth to 10 years (lifetime), postnatal day 300 to 10 years ( postinfancy), and postnatal day 0-400 (infancy); monkeys in the contro l group received only the vehicle (95% glycerol and 5% distilled water ). At age 10 years, circulating lead concentrations in lifetime and po stinfancy-dosed monkeys were approximately 35 mu g/dL, and in control and infancy animals the concentrations were <1.0 mu g/dL. Sertoli and spermatogenic cells of dosed monkeys from the infancy and lifetime gro ups revealed injuries. Chronic exposure to lead that results in modera te blood lead concentrations induced persistent ultrastructural altera tions in the cynomolgus monkey testis. Results of this study on the pr imate, following extrapolation to humans, could influence further refi ning of the impact of environmental lead contamination concentrations vis-a-vis the health of children, adults, and aged human beings.