IMPAIRMENT OF TESTICULAR ENDOCRINE FUNCTION AFTER LEAD-INTOXICATION IN THE ADULT-RAT

To clarify the mechanism of the action of lead on male reproductive fu nction, adult male rats were injected intraperitoneally (i.p.) with le ad acetate (8 mg/kg/day of lead), 5 days a week for 35 days. Despite t his high dose, germ cells and Sertoli cells did not appear to be major targets of lead. However, lead determination in the reproductive orga ns showed that the accessory sex glands are such a target, Epididymal function was unchanged. In lead-exposed rats, plasma and testicular te stosterone dropped by about 80%, but plasma luteinizing hormone (LH) o nly dropped by 32%. After luteinizing hormone releasing hormone (LHRH) stimulation of the pituitary, the plasma LH level reached the control one, but plasma testosterone remained significantly reduced by 37%. T he sharp decrease in the testosterone:LH ratio in lead-exposed rats, c ombined with the significant reduction of intertubular tissue volume i n the testes, indicate impaired Leydig cell function.