Influence of morphine exposure during adolescence on the sexual maturation of male rats and the development of their offspring.

The effects of adolescent morphine exposure on the sexual maturation of male rats, their reproductive capacity and the development of their progeny were examined. Groups of prepubescent male rates (25-27 days of age) were implanted with morphine- or placebo-pellets (one on Day 1, then two pellets on Days 4, 7 and 10); the pellets were not removed to assure the sustained release of morphine for 3 to 4 weeks and to avoid the confounding effects of a precipitated withdrawal syndrome. Groups of animals were sacrificed at weekly intervals through adulthood for an assessment of reproductive endocrine function. A large group, however, was also bred with drug-naive primiparous females at 85 days of age (8 weeks after morphine or placebo pellet implantation), when the acute and chronic effects of morphine on reproductive endocrine parameters had dissipated; their fertility and the development of the male and female progeny was characterized. Our results indicated that morphine exposure during adolescence led to a pronounced inhibition of a number of indices of sexual maturation (e.g., serum testosterone and luteinizing hormone levels and reduced weights of the testes and seminal vesicles). Breeding morphine- and placebo-implanted male rats with drug-naive females resulted in smaller liters derived from morphine-treated fathers when compared to controls, but in all other respects the development of the offspring in the two groups were equivalent. However, upon reaching adulthood, a number of selective endocrine differences were detected in morphine-derived offspring when compared to controls.(ABSTRACT TRUNCATED AT 250 WORDS)