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1 July 2001 Effect of Seminal Phospholipid-Binding Proteins and Follicular Fluid on Bovine Sperm Capacitation
Isabelle Thérien, Daniel Bousquet, Puttaswamy Manjunath
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Bovine seminal plasma (BSP) contains a family of novel phospholipid-binding proteins (BSP-A1/-A2, BSP-A3, and BSP-30-kDa; collectively called BSP proteins) that potentiate sperm capacitation induced by heparin or by serum high-density lipoprotein (HDL). BSP proteins stimulate lipid efflux from sperm that may occur during the early events of capacitation. Here, we investigated the role of BSP proteins, bovine follicular fluid (FF), and bovine follicular fluid HDL (FF-HDL) in sperm capacitation. FF and FF-HDL alone stimulated epididymal sperm capacitation (19.5% ± 0.8% and 18.2% ± 2.8%, respectively, control, 9.0% ± 1.9%) that was increased by preincubation with BSP-A1/-A2 proteins (30.2% ± 0.4% and 30.9% ± 1.5%, respectively). In contrast, lipoprotein-depleted follicular fluid (LD-FF) alone was ineffective, and a preincubation with BSP-A1/-A2 proteins was necessary before sperm capacitation was stimulated (up to 22.8% ± 1.4%). The interaction of BSP proteins with FF components was analyzed using ultracentrifugation, Lipo-Gel electrophoresis, SDS-PAGE, and gel filtration. We established that the BSP proteins interact with factors present in FF including FF-HDL. Additionally, we obtained evidence that BSP proteins, found associated with FF-HDL, were released from the sperm membrane during capacitation. These results confirm that the BSP proteins and the FF-HDL play a role in sperm capacitation.

Isabelle Thérien, Daniel Bousquet, and Puttaswamy Manjunath "Effect of Seminal Phospholipid-Binding Proteins and Follicular Fluid on Bovine Sperm Capacitation," Biology of Reproduction 65(1), 41-51, (1 July 2001).
Received: 27 October 2000; Accepted: 1 February 2001; Published: 1 July 2001

acrosome reaction
female reproductive tract
male reproductive tract
seminal vesicles
sperm capacitation
sperm maturation
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