Glycolysis and sperm motility: does a spoonful of sugar help the flagellum go round?
Glycolysis and sperm motility: does a spoonful of sugar help the flagellum go round?
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DOI：
10.1093/humupd/dmi053
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发表时间：
2006-05-01
影响因子：
13.3
通讯作者：
Ford, WCL
中科院分区：
文献类型：
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作者：
Ford, WCL
这是值得怀疑的，扩散可以提供足够的ATP从线粒体维持活动在远端的精子鞭毛。与纤维鞘结合的糖酵解酶可以在需要的地方沿着鞭毛提供能量。糖酵解的一个强制性作用是由缺乏前向运动的小鼠精子中的精子特异性甘油醛-3-磷酸脱氢酶（GAPDH）的基因已被“敲除”。在这里，我回顾了一些反对这一观点的证据。首先，从精子的纯扩散可能是足够的，在较小的精子物种，它是可能的，快速ATP输送所需的较大的精子可以实现的腺苷酸激酶穿梭。其次，α-氯乙醇的经验表明，尽管GAPDH受到抑制，但精子在正常ATP浓度下仍能保持活力;只有在加入葡萄糖和高水平糖酵解中间产物积累时才会发生不良反应。这些观察结果破坏了GAPDH基因敲除小鼠作为局部糖酵解重要作用的证据。第三，许多物种的精子可以在无糖培养基中长时间保持运动能力，除了狗的精子之外，糖异生是一种可能的解释的证据很弱。在大多数物种中，局部糖酵解不太可能是ATP供应到远端鞭毛的唯一途径。
It is doubtful that diffusion can deliver sufficient ATP from the mitochondria to sustain activity at the distal end of the sperm flagellum. Glycolytic enzymes bound to the fibrous sheath could provide energy along the flagellum at the point it is required. An obligatory role for glycolysis is supported by the lack of progressive motility in sperm from mice where the gene for sperm-specific glyceraldehyde-3-phosphate dehydrogenase (GAPDHs) had been 'knocked out'. Here, I review some evidence against this idea. First, pure diffusion from the mitochondrion is likely to be adequate in species with smaller sperm, and it is possible that rapid ATP delivery required in larger sperm could be achieved by an adenylate kinase shuttle. Second, experience with alpha-chlorohydrin demonstrates that sperm can remain motile with normal ATP concentrations despite inhibition of GAPDHs; adverse effects only occur if glucose is added and high levels of glycolytic intermediates accumulate. These observations undermine the GAPDHs knockout mouse as evidence for an essential role of local glycolysis. Third, sperm from many species can remain motile for long periods in sugar-free media and excepting dog sperm, evidence that gluconeogenesis is a possible explanation, is weak. In most species, it is unlikely that local glycolysis is the only way that ATP can be supplied to the distal flagellum.