Differential effects of cefmetazole sodium on the reproductive system of infant and pubertal male rats

Abstract

The effects of cefmetazole (CMZ), a cephem antibiotic which contains the N-methyltetrazolethiol (NMTT) side-chain moiety, were compared in infant (6–42 days of age) and pubertal (6–10 weeks of age) male Sprague-Dawley rats. High doses of either CMZ or free NMTT caused reductions in testicular weight and delayed maturation of spermatogenic germ cells in the testes of infant rats, implicating NMTT as the active component in causing these effects. Pubertal rats expressed neither of these effects, even when treated with doses of CMZ far in excess of those used in infant rats. The effects of CMZ and NMTT on testicular weights and histologic features of testes of rats treated as infants were mainly reversed when these animals were examined 35 and 70 days after cessation of treatment. All reproductive functional parameters were normal in mating studies using male rats which had been treated with CMZ or NMTT as infants and allowed to recover. Because of the species differences in rates of sexual maturation and the greater rate at which rats metabolize CMZ to NMTT, the relevance to humans of the testicular effects of CMZ in infant rats is unknown.