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Effect of ovulation on sperm transport in the hamster oviduct

1991; Bioscientifica; Volume: 93; Issue: 1 Linguagem: Inglês

10.1530/jrf.0.0930157

1741-7899

Masaya Ito, T. Timothy Smith, Ryuzo Yanagimachi,

Ovarian function and disorders

Summary. When hamsters mate shortly after the onset of oestrus (4·5–6 h before the onset of ovulation), spermatozoa are stored in the caudal isthmus of the oviduct until near the time of ovulation. At this time, a few spermatozoa ascend to the ampulla to fertilize the eggs. Superovulation resulted in a significant increase in the number of spermatozoa in the caudal isthmus at 6 h post coitus (p.c.) and in the ampulla and bursal cavity at 12 h p.c. Precocious ovulation resulted in a highly significant reduction in the total number of spermatozoa in the oviduct at 3 and 6 h p.c. This effect was completely overcome by intrauterine artificial insemination, suggesting lack of cervical patency as the block to sperm transport in precociously ovulated animals. Ligation of the ampulla–infundibulum junction in naturally ovulating hamsters resulted in significantly fewer spermatozoa in the caudal isthmus and ampulla at 12 h p.c. Preclusion of ovulation also resulted in fewer spermatozoa in the caudal isthmus and ampulla at 12 h p.c., suggesting that the products of ovulation stimulate sperm transport in the oviduct. Keywords: sperm transport; superovulation; precocious ovulation; oocyte-cumulus complex; hamster