Two modifiers of sperm transport within the fallopian tube of the rat

In several mammals studied, ovulation appears to stimulate coordinated translocation of a few potential fertilizing spermatozoa to the ampulla from the caudal isthmus of the Fallopian tube. The present experiments demonstrate that, in the rat, this movement is regulated to a considerable degree within each duct by the ipsilateral ovary. Unilateral ovariectomy had no effect on ipsilateral sperm transport into the uterus, but this brought a unilateral quenching of sperm transport to the ampulla of the oviduct, from which spermatozoa were often totally or almost absent. This suppression was always complete on the ipsilateral side in unilaterally ovariectomized females anaesthetized with sodium pentobarbital soon after ovulation, and was evident bilaterally also at a highly significant level among intact females that were anaesthetized in this way. Unilateral ovariectomy and sodium barbital anaesthesia could provide experimental situations through which to decipher the mechanisms of normal sperm transport in the Fallopian tube.