Polyol pathway along the bovine epididymis
Polyol pathway along the bovine epididymis
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DOI：
10.1002/mrd.20170
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发表时间：
2004-12-01
影响因子：
2.5
通讯作者：
Sullivan, R
中科院分区：
文献类型：
--
作者：
Frenette, G;Lessard, C;Sullivan, R
在附精过程中，雄配子获得受精所需的新的表面蛋白。我们之前已经证明，称为附睾体的膜性小泡与附睾液中的精子表面相互作用，允许一些蛋白质转移到精子的不同亚细胞室。我们先前发现与附睾体相关的主要蛋白质之一是醛糖还原酶(基因：AKR1B5)，并证实该酶位于附睾腔内交界处的上皮细胞中。结果表明，在附睾体的近、中段，胞浆醛缩合还原酶活性最高，而在远端则下降。Western和Northern印迹分析证实了ALCLOSE还原酶及其编码基因的分布模式。以葡萄糖为底物时，附睾醛缩合还原酶的最适pH为6.0~6.5，与附睾腔内液体的pH值一致。为了评价山梨醇在精子生理中的作用，用抗山梨醇脱氢酶抗体对组织匀浆进行了Western印迹检测。附睾近端和远端的酶免疫测定量高于附睾中段。山梨醇脱氢酶活性与编码基因的水平呈现相同的分布规律。此外，使用抗山梨醇脱氢酶的免疫组织学研究表明，该酶是由附睾上皮细胞与管腔内交界处合成的。知道山梨醇和果糖在精子新陈代谢中的重要性，我们假设多元醇途径参与了附睾内精子运动的调节。(C)2004年Wiley-Liss公司
During the epididymal transit, male gametes acquire new surface proteins necessary for their fertilizing ability. We have previously shown that membranous vesicles, called epididymosomes, interact with sperm surface within the epididymal fluid allowing transfer of some proteins to different subcellular compartments of spermatozoa. We previously showed that one of the major proteins associated with epididymosomes was an aldose reductase (gene: AKR1B5) and confirmed that aldose reductase is located in the epithelial cells bordering the intraluminal compartment of the epididymis. The present study shows that cytosolic alclose reductase activity was maximal in the proximal and middle segments of the epididymis and decreased in the distal epididymis. Western and Northern blot analysis confirmed the distribution pattern of alclose reductase and of the encoding mRNA. The optimal pH of epididymal alclose reductase was 6.0-6.5 when glucose was used as a substrate; this corresponds to the pH of the intraluminal epididymal fluid. In order to evaluate the possible involvement of sorbitol in sperm physiology, Western blot of tissue homogenates were probed with an anti-sorbitol dehydrogenase antibody. The amount of enzyme immunodetected was higher in the proximal and distal segments of the epididymis when compared to the amount detectable in the middle segment of the epididymis. Sorbitol dehydrogenase activity as well as the level of the encoding mRNA showed the same pattern of distribution. Furthermore, immunohistological studies using the anti-sorbitol dehydrogenase revealed that this enzyme was synthesized by the epididymal epithelial cells bordering the intraluminal compartment. Knowing the importance of sorbitol and fructose in sperm metabolism, we hypothesized that the polyol pathway is involved in the modulation of sperm motility within the epididymis. (C) 2004 Wiley-Liss, Inc.