Properties of decapacitation factor and presence in various species.

A delay between the optimum time for insemination and the time of ovulation a uterine incubation period for spermatozoa (capacitation) observed in some species is related to the presence of a decapacition factor (DF) in seminal plasma which functionally reverses the capacitation process. Spermatozoa were removed by centrifugation from rabbit bull stallion boar monkey rooster dog and human semen. A DF pellet of partially purified DF was prepared from monkey and bull seminal plasma. In other species whole seminal plasma was assayed. Capacitated spermatozoa recovered from the uterus of a doe 11 hours after mating were incubated with bull DF pellet and rabbit plasma at a level of 1 mg biuret-reactive-material (BRM)/100000 spermatozoa with monkey DF pellet at 2 mg BRM/100000 and with seminal plasma of the remaining species at 5 mg BRM/100000 spermatozoa. DF treated capacitated spermatozoa were introduced into one oviduct of a doe 12 hours after administration of an ovulatory dose of LH (3.1 mg.) An equal number of untreated capacitated spermatozoa were inseminated into the second oviduct. Recapacitation was demonstrated in does inseminated with untreated capacitated spermatozoa in one horn and with washed ejaculated spermatozoa in the other. Does were killed 26 hours or less after ovulation. The uteri of does in seminated with bull rabbit boar stallion and monkey seminal plasma treated spermatozoa showed no fertilized ova while control uteri for each group showed mean percent fertilized ova of 54.8 87.4 35.8 70.0 and 85. 2% respectively. Rooster dog and human seminal plasma showed no DF activity. No fertilized ova were found after insemination with capacitated spermatozoa and seminal plasma incubated with crude-neuraminidase-lecithinase (Vacholera filtrate) pronase lysozyme alpha-amylase glucose oxidase or hyaluronidase compared to 37.6 to 63.7% of ova fertilized in the control oviducts. Beta-amylase destroyed DF activity with 53.4% ova fertilized compared to a mean 50.8% in the control oviducts. When a DF pellet replaced seminal plasma alpha-amulase and beta-amylase destroyed the activity of partially purified DF with 5.9% and 26.2% ova fertilized respectively and 59.5% and 50.8% ova fertilized in the control oviducts. It has been observed that amylase content of uterine fluid elevated at the time when capacitation normally occurs. Incubation of capacitated spermatozoa with sialic acid previous to incubation with a DF factor did not prevent decapacitation after insemination. Incubation of uterine spermatozoa with sialic acid sialyl lactose or maltose before insemination did not prevent normal capacitation. It is possible that capacitation is required in humans but the DF is to specific to decapacitate rabbit spermatozoa.