Effect of local epididymal levonorgestrel on the fertilizing ability of male rat, a model for post-testicular contraception

A thin levonorgestrel-silicone layer was applied on the capsule of the caud a epididymis of male rats to study a model for post-testicular male contrac eption. The effect of different levonorgestrel doses on the fertility of ma les was tested with fertile females. The time-dependent influence of a stan dard dose of levonorgestrel on serum LH and on testicular histology was est imated. Among the males tested, there was a group of animals where successf ul contraception with local application of levonorgestrel-silicone membrane was obtained. Sexual behavior was normal and the spermatogenesis was funct ioning, but the sperm were infertile. Although further research is needed t o estimate adequate dose and strength of levonorgastrel in silicone matrix, this study shows that post-testicular contraception is possible to achieve . CONTRACEPTION 2000;61: 401-406 (C) 2000 Elsevier Science Inc. All rights reserved.