Title: An influx of extracelluar calcium is required for initiation of the human sperm acrosome reaction induced by human follicular fluid
Abstract: Abstract The role of Ca 2+ in the human sperm acrosome reaction was investigated using the fluorescent calcium indicator fura‐2. Previous experiments have shown that a Sephadex G‐75 column fraction of human follicular fluid can stimulate the human sperm acrosome reaction [Suarez SS, Wolf DP, Meizel S (1986): Gamete Res 14:107–121]. Using fura‐2, we demonstrated that this Sephadex G‐75 fraction also stimulates a rapid, transient increase in intracellular free Ca 2+ . This Ca 2+ transient is blocked either by chelation of extracellular calcium or by addition of the Ca 2+ antagonist La 3+ . We have also been able to stimulate the acrosome reaction in human sperm without significant loss of motility, using the divalent cation ionophore ionomycin. Acrosome reactions stimulated by whole follicular fluid, the G‐75 fraction, or ionomycin are all blocked by removal of extracellular Ca 2+ . These results strongly suggest that an influx of extracellular Ca 2+ is responsible for intiating the acrosome reaction in human sperm treated with human follicular fluid. This is the first demonstration in mammalian sperm that a potentially physiological stimulus can cause an increase in intracellular Ca 2+ concomitant with the acrosome reaction.
Publication Year: 1988
Publication Date: 1988-08-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 207
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