Influence of concurrent testosterone on the effects of methadone on male rats and their progeny.

This study was conducted to test the hypothesis that the adverse effects on progeny that result from administering methadone to male rats are mediated by a decrease in serum testosterone. Male rats were treated with methadone HCl, 10 mg/kg/day for 4 days while an equal number received the same dose plus testosterone propionate, 2.5 mg/kg/day. Neonatal mortality was significantly lower among the progeny of sires which had received the testosterone, 22/132 vs. 33/101, x2 = 8.13, p less than 0.01. The mean body weight at weaning of the progeny of sires treated with methadone plus testosterone was about 4 g lower (p less than 0.01) than that of the progeny of sires which had received methadone only; one-half of this variability was attributable to the greater number of survivors in the former group. Testosterone administered concurrently with methadone to sires resulted in significant reductions in the weights of their testes and adrenals, but increased weights of their seminal vesicles. It was concluded that administration of testosterone concurrent with methadone by preventing dysfunction and/or atrophy of the accessory sex organs of the sire, may have been responsible for the improved neonatal survival of their offspring.