Failure of seminal plasma to enter the uterus and oviducts of the rabbit following artificial insemination.

Twelve adult does in estrus were artificially inseminated with 1 ml of semen from bucks that had received injections of 3H-thymidine 22 to 32 days previously. The ejaculates contained radioactive seminal plasma and unlabeled sperm. The reproductive tracts of the does were removed at selected intervals after insemination, divided into segments of no more than 300 mg, and processed for scintillation counting. Significant levels of radioactivity were never detected in any uterine or oviductal segment. The technique was capable of detecting as little as 1.5 X 10(-4) ml of semen in a segment. These results demonstrate that seminal plasma is not transported from the vagina into the uterus or oviducts in the rabbit, emphasizing the importance of the motility of spermatozoa in their passage to the site of fertilization.