The process of capacitation is poorly understood for ejaculated sperm. We have shown that ejaculated sperm undergo the acrosome reaction in the ampulla of the oviduct. A lysophosphatidylcholine (LC) sensitivity test was developed to separate capacitation from the acrosome reaction. A sperm capacitating factor possessing characteristics of heparin or heparan sulfate was found in oviduct fluid. Capacitation induced by heparin was Ca++ dependent and blocked by glucose with the block reversed by 8-bromo cAMP. The presence of seminal plasma alters sperm capacitation characteristics by inhibiting spontaneous capacitation of epididymal sperm. We hypothesize that the ejaculated sperm capacitating factor of oviduct fluid is heparan sulfate and that it is either masked or modulated during the estrous cycle such that only estrual oviduct fluid capacitates ejaculated sperm. We further hypothesize that capacitating agents capacitate sperm by first binding to sperm followed by sterol depletion and modification of the plasma membrane resulting in Ca++ uptake. We propose to test hypotheses supporting the following aims: A) to identify naturally occurring sperm capacitating agents in the bovine oviduct; by isolation of the factor using HPLC and affinity chromatography and by use of the LC sensitivity and in vitro fertilization assays we have developed to detect capacitation of bovine sperm. The factor will be identified from its structural characteristics. B) To determine the mechanism whereby capacitating agents cause capacitation of bovine sperm; by determining if binding of the agent to sperm is required, if cholesterol efflux occurs, if cAMP levels are modulated and if capacitation is dependent on Ca++ and blocked by agents blocking Ca++ uptake. C) To identify and isolate by HPLC, seminal plasma components which inhibit capacitation in vitro and to determine using the techniques of Aim B, the mechanisms whereby they prevent capacitation of bovine sperm. These experiments will for the first time isolate and identify capacitating agents from the mammalian oviduct. Results of these experiments will enhance our understanding of how capacitation occurs and thus our ability to manipulate the fertilization process.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD018345-05
Application #
3315382
Study Section
Reproductive Biology Study Section (REB)
Project Start
1984-01-01
Project End
1990-03-31
Budget Start
1988-04-01
Budget End
1989-03-31
Support Year
5
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of Wisconsin Madison
Department
Type
Earth Sciences/Resources
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
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Parrish, J J; Susko-Parrish, J L; Handrow, R R et al. (1989) Capacitation of bovine spermatozoa by oviduct fluid. Biol Reprod 40:1020-5
Parrish, J J; Susko-Parrish, J L; Handrow, R R et al. (1989) Effect of sulfated glycoconjugates on capacitation and the acrosome reaction of bovine and hamster spermatozoa. Gamete Res 24:403-13
Parrish, J J; Susko-Parrish, J L; First, N L (1989) Capacitation of bovine sperm by heparin: inhibitory effect of glucose and role of intracellular pH. Biol Reprod 41:683-99
Handrow, R R; First, N L; Parrish, J J (1989) Calcium requirement and increased association with bovine sperm during capacitation by heparin. J Exp Zool 252:174-82
Parrish, J J; Susko-Parrish, J; Winer, M A et al. (1988) Capacitation of bovine sperm by heparin. Biol Reprod 38:1171-80
First, N L; Parrish, J J (1987) In-vitro fertilization of ruminants. J Reprod Fertil Suppl 34:151-65
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Herz, Z; Northey, D; Lawyer, M et al. (1985) Acrosome reaction of bovine spermatozoa in vivo: sites and effects of stages of the estrous cycle. Biol Reprod 32:1163-8