In vivo capacitation and acrosome reaction of bovine sperm in estrous and diestrous cows.
A staining procedure which enables distinction between spermatozoa possessing a true and false acrosome reaction (AR) was utilized to assess the incidence of capacitation and the true AR of bull spermatozoa recovered from the uterine horns of estrous and diestrous cows. Results show that at 3 and 6 h post-insemination, approximately 14.5 and 31.5%, respectively, of the live spermatozoa recovered had undergone a true AR in the uterus of estrous cows. An increasing percentage of those spermatozoa recovered from estrous cows with time were categorized as undergoing a false AR. This suggests that spermatozoa underwent capacitation, a true AR, then died prior to fixation and staining, therefore being grouped as false acrosome-reacted. Few spermatozoa were observed to have undergone a true AR in diestrous cows. It is apparent from this study that individual spermatozoa undergo capacitation and a true AR at different times during incubation in utero in estrous cows.
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Didion
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Graves
D000177:Acrosome / Q000502:physiology*; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004031:Diestrus; D004971:Estrus; D005260:Female; D008297:Male; D013075:Sperm Capacitation; D013094:Spermatozoa / Q000502:physiology*; D013194:Staining and Labeling