精子活动的能量由糖酵解途径产生

研究男性不育的专家发现：糖酵解途径的关键成分，甘油醛-3-磷酸脱氢酶(glyceraldehyde 3-phosphate dehydrogenase, GAPD)在精子细胞生成迁移至卵子所需能量过程中是必不可少的，

美国北卡罗莱纳大学医学院(Chapel Hill, NC, USA)的研究人员，通过基因工程培养了一个不表达GAPDS基因的小鼠品系，GAPDS是小鼠精子细胞中存在的酶。研究人员在2004年11月6日《美国国立科学院学报》在线版报道说：尽管这些动物能够与正常的雌性小鼠进行交配，这些小鼠都不能生育。在显微镜下检查了小鼠精子发现，精子只能进行侧向移动，却不能向前移动。

在生化水平发现尽管线粒体氧消耗没有发生改变，但是来自这些小鼠精子的三磷酸腺苷(adenosine triphosphate, ATP)水平只有对照小鼠的10.4％。由此可见，精子活动所需的大部分能量是由糖酵解产生的，而不是氧化磷酸化。

美国北卡罗莱纳大学医学院细胞与发育生物学副教授、高级作者Deborah O'Brien博士说：“我们对这些发现十分惊奇，这证实了几乎全部精子活力与ATP的产生都依赖于这个酶。“

因为人类精子中存在GAPD，作者提示该酶可以成为避孕药物的一个良好的作用靶点，而环境中存在的能够影响其活性的化学制剂可能与人类男性不育有关。
 
Glycolysis Produces the Power for Sperm Motility
 
Researchers studying male infertility have found that the enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPD), a key component of the glycolysis pathway, is required to produce the energy needed by sperm cells to migrate towards the awaiting eggs.

Investigators at the University of North Carolina Medical School (Chapel Hill, NC, USA) genetically engineered a line of mice lacking the gene for GAPDS, the form of the enzyme found in mouse sperm cells. They reported in the November 16, 2004, online edition of the Proceedings of the [U.S.] National Academy of Sciences that while these animals mated normally with receptive female mice, they were infertile. Examination of their sperm under the microscope revealed that the sperm showed only a slight side-to-side movement, but were incapable of moving forward.

At the biochemical level it was found that although mitochondrial oxygen consumption was unchanged, sperm from these mice had adenosine triphosphate (ATP) levels that were only 10.4% of those in sperm from control mice. Thus, most of the energy required for sperm motility was generated by glycolysis rather than oxidative phosphorylation.

“We were very surprised at this finding,” said senior author Dr. Deborah O’Brien, associate professor of cell and developmental biology at the University of North Carolina School of Medicine. “It turned out that almost all of the sperm’s motility and ATP production depended on this enzyme.”

Since a form of GAPD is present in human sperm, the authors suggested that it might be a good target for contraceptive agents, and that environmental agents that affect its activity may be related to male infertility in humans.