Metabolic and surface events in fertilization

Fraser, Lynn R.; Ahuja, Kamal

doi:10.1002/mrd.1120200409

Cited by 89 publications

(46 citation statements)

References 149 publications

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“…2). Capacitation is regulated by a number of factors including cAMP (see Fraser & Ahuja, 1988;Garbers, 1989) and caffeine can enhance the penetrating power of poor quality sperm suspensions in the hamster egg test (Aitken et ai, 1983;Prins & Ross 1985;Cai & Marik, 1989). However, the motility changes observed here are quite different from the type of hyperactivated or 'whiplash' motility seen in capacitating mouse or hamster spermatozoa (see Fraser, 1984) and the complex 'star-spin' and related trajectories observed in human spermatozoa (Robertson et ai, 1988).…”

Section: Discussionmentioning

confidence: 99%

Effect of caffeine and of pentoxifylline on the motility and metabolism of human spermatozoa

Rees¹,

Ford²,

Hull³

1990

Reproduction

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Section: Discussionmentioning

confidence: 99%

Effect of caffeine and of pentoxifylline on the motility and metabolism of human spermatozoa

Rees¹,

Ford²,

Hull³

1990

Reproduction

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“…Physiological processes in the oviduct that influence mammalian fertilisation have been reviewed in recent years in a number of key publications (Gwatkin, 1977;Bedford, 1982;Fraser, 1984;Fraser and Ahuja, 1988;Hunter, 1988;Yanagimachi, 1988). By contrast, the etiology of polyspermic fertilisation has received very little attention, even though polyspermy may arise in vivo under diverse experimental conditions.…”

Section: Introductionmentioning

confidence: 99%

Oviduct function in pigs, with particular reference to the pathological condition of polyspermy

Hunter

1991

Molecular Reproduction Devel

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Because the exceptionally high incidence of polyspermic fertilisation has been emphasised as a major defect in systems of in vitro fertilisation in pigs, the aetiology of the condition has been analysed in a series of experiments in vivo in the search for a common underlying cause and possible means of mitigation. Whereas the defense mechanism against polyspermy in pig oocytes is classically viewed as a zona reaction, more recent evidence suggests a secondary block at the vitelline surface. Both blocks may be compromised in situations leading to polyspermy, although deleterious influences seem to be expressed principally in an inadequate zona block, as judged by the presence of perivitelline spermatozoa.Postovulatory aging of mammalian oocytes prior to sperm penetration leads to polyspermy, as can be demonstrated in pig eggs. The primary lesion may concern the cortical reaction, owing to a delayed and incomplete exocytosis of the vesicular contents. Eggs ovulated after gonadotrophin treatment during the luteal phase of the cycle show a high incidence of polyspermic penetration (60.6%), as do those shed at estrus in animals treated with progesterone systemically (40%) or by local microinjections in the oviduct wall (32.3%). Whereas progesterone may be modifying interactions of the gametes and responses of the egg organelles in all four above experimental situations, enhanced numbers of spermatozoa ascending a more patent isthmus appear to be the principal cause of polyspermy. Support for this hypothesis comes from isthmus resection with re-anastomosis of remaining portions of the oviduct (32.4% polyspermy), and surgical insemination directly into the oviducts (33.8% polyspermy). Recent experiments draw attention to a role for oviduct epithelial glycoproteins in modulating the extent of polyspermy in vitro. The role of such oviduct macromolecules in gamete interactions in vivo is considered.

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“…Freshly ejaculated spermatozoa are unable to fertilize oocytes, but they acquire functional competence following their removal from seminal plasma and sufficient incu¬ bation in permissive conditions, the length required being species-dependent (Bedford, 1970(Bedford, , 1983. Capacitation is a complex phenomenon involving changes in intracellular and surface com¬ ponents which prepare spermatozoa for the AR (Fraser & Ahuja, 1988). The latter involves the structural breakdown of the plasma and outer acrosomal membranes, resulting in the release of lytic enzymes.…”

Section: Introductionmentioning

confidence: 99%

Extended exposure to follicular fluid is required for significant stimulation of the acrosome reaction in human spermatozoa

Stock¹,

Bates²,

Lindsay³

et al. 1989

Reproduction

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Summary. The effect of human follicular fluid (FF) on the incidence of spontaneous acrosome reactions (AR) in human spermatozoa was examined over a 24\p=n-\25-h period using electron microscopy. Suspensions of motile spermatozoa were prepared by a swim-up method in Earle's medium, known to support in-vitro fertilization. After adjusting the concentration to 10 \m=x\106 cells/ml, suspensions were diluted 1:1 with medium (control) or FF, the latter giving a final concentration of 50% FF. In addition, at 5 h and 24 h an aliquant of the control suspension was removed, diluted 1:1 with FF and incubated for 1 h; the three suspensions were examined at 6 h and 25 h. Continuous exposure to 50% FF stimulated the AR, the effect being significant (P < 0\m=.\001) at 25 h. However, the 1-h short exposure of spermatozoa to FF did not produce an increase in AR, even after 24 h preincubation. In a separate series of experiments, the effect of continuous incubation for 24 h in increasing concentrations of FF was investigated. A significant linear dose-dependent effect on the AR was observed with all concentrations assessed (P < 0\m=.\01for 12\m=.\5%FF and P < 0\m=.\001for 25, 50, 75 and 100% FF, compared with FF-free control). Therefore, human FF can stimulate the AR, but only after a continuous exposure to FF. A short exposure to FF, even after 24 h preincubation, does not trigger an increased AR response.

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Metabolic and surface events in fertilization

Cited by 89 publications

References 149 publications

Effect of caffeine and of pentoxifylline on the motility and metabolism of human spermatozoa

Effect of caffeine and of pentoxifylline on the motility and metabolism of human spermatozoa

Oviduct function in pigs, with particular reference to the pathological condition of polyspermy

Extended exposure to follicular fluid is required for significant stimulation of the acrosome reaction in human spermatozoa

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