The stimulation of bovine caudal epididymal sperm forward motility by bovine cumulus-egg complexes in vitro.

We have determined the effects of cumulus oophorus-egg complexes, and of separated eggs and cumulus oophorus cells on bovine sperm forward motility. The forward motility index of spermatozoa was elevated by the incubation of spermatozoa in the presence of cumulus oophorus-egg complexes. Subsequently, it was shown that these complexes could release substance(s) into the medium which stimulated sperm motility. FSH appeared to cause a greater release of the stimulatory substance(s) from the cumulus oophorus-egg complexes. Separation of cumulus oophorus cells from eggs demonstrated that the stimulatory factor(s) were being released from the cumulus oophorus cells and not the eggs. These results demonstrate that bovine cumulus oophorus cells associated with the egg can influence spermatozoan motility.