Spermicidal effects of amphotericin B and nystatin on bull and rabbit sperm and contraceptive effects in rabbits.

Vaginal contraceptives have potential for controlling reproduction as well as sexually transmitted diseases. Two extensively used fungicides, amphotericin B and nystatin, were found to be highly spermicidal to bull and rabbit sperm even in the presence of organic material found in milk and egg yolk, both excellent components of media designed to preserve sperm. In repeated tests with many samples of bull and rabbit sperm, as little as 0.5 micro g/mL of amphotericin B completely immobilized sperm after prolonged exposure, and 1000 micro g/mL immobiled sperm in less than 1 min. Treatment of rabbit sperm with 1000 micro g of solubilized amphotericin B in 0.4 ml of a glucose-semen mixture before insemination resulted in a total of 2 young born from 9 inseminated Dutch does, compared with 55 young from 9 control does. As this inhibition was achieved without the use of enhancing foams or gels, these results provide promising leads for contraceptive research.