EPIDIDYMAL GLUTATHIONE--PHYSIOLOGIC & MOLECULAR STUDIES

当精子沿着附睾管前进时，它们沐浴在 特殊的管腔流体微环境， 成熟和生存。 随着精子的成熟，它们需要持续的 保护免受氧化损伤和药物的有害影响， 有毒化学物质。 受损的精子可能会导致后代畸形。 在 许多组织如肺和肾，谷胱甘肽（glu-cys-gly） 已经被证明在抗氧化防御中起着重要作用，而且似乎 它可能在附睾中起着类似的作用。 的重点 建议是确定管腔谷胱甘肽是如何 由附睾上皮调节。 我们将使用活体显微穿刺 和微灌注技术，以确定谷胱甘肽的来源， 附睾不同区域的腔液。 康贝特人将以 γ-谷氨酰转肽酶（GGT）的活性，GGT是唯一已知的 可以裂解谷胱甘肽产生谷氨酸和二肽半胱氨酸， 甘氨酸 还将进行实验以确定催化剂。 将半胱氨酸-甘氨酸切割成其组分的二肽酶的活性 个氨基酸 GGT可以转运半胱氨酸和甘氨酸的假说 将测试从管腔进入附睾细胞。 我们有 先前发现，管腔GGT催化活性从头部下降到 尾。 因此，将设计实验以确定 附睾尾内GGT活性丧失的机制 区域，无论是由于蛋白酶降解酶和/或 位于腔液内和/或顶端的内切糖苷酶 尾部上皮细胞表面。 利用分子生物学技术 我们将鉴定表达GGT mRNA的附睾细胞类型。 因此，我们认为， 我们将识别出那些在调节中起重要作用的细胞， 附睾谷胱甘肽 我们必须了解 附睾维持环境的机制， 保护精子免受氧化和各种有害影响 药物和外源性物质;氧化防御是至关重要的生存 精子 该提案是了解 附睾维持最佳管腔功能的机制 精子成熟和存活的微环境。 这一发现 该提案还将为制定一项 男性避孕药和治疗某些形式的男性不育症。

As spermatozoa progress along the epididymal duct, they are bathed in a specialized luminal fluid microenvironment which is crucial for their maturation and survival. As the spermatozoa mature, they need constant protection against oxidative damage and from harmful effects of drugs and toxic chemicals. Damaged spermatozoa may lead to abnormal offspring. In many tissues such as the lung and kidney, glutathione (glu-cys-gly) has been shown to play an important role in antioxidant defense, and it seems likely that it plays a similar role in the epididymis. The focus of this proposal is to determine the manner by which luminal glutathione is regulated by the epididymal epithelium. We will use in vivo micropuncture and microperfusion techniques to determine the origin of glutathione in the luminal fluid of different epididymal regions. We will determine the activity of gamma-glutamyl transpeptidase (GGT), the only known enzyme that can cleave glutathione to yield glutamate and the dipeptide cysteine- glycine. Experiments will also be performed to determine the catalytic activity of dipeptidase which cleaves cysteine-glycine into its constituent amino acids. The hypothesis that GGT can transport cysteine and glycine from the lumen into the epididymal cells will be tested. We have previously found that luminal GGT catalytic activity declines from caput to cauda. Therefore, experiments will be designed to determine the mechanism(s) of the loss of GGT activity within the cauda epididymal region, whether it is due to degradation of the enzyme by proteases and/or endoglycosidases located within the luminal fluid and/or on the apical surface of cauda epithelial cells. Using molecular biological techniques we will identify the epididymal cell type(s) that express GGT mRNA. Hence, we will identify those cells that play an important role in the regulation of epididymal glutathione. It is critical that we understand the mechanisms by which the epididymis maintains an environment that will protect spermatozoa from oxidation and from harmful effects of various drugs and xenobiotics; oxidative defense is crucial for the survival of spermatozoa. This proposal is part of a long term goal to understand the mechanisms by which the epididymis maintains an optimal luminal microenvironment for sperm maturation and survival. The findings from this proposal will also provide fundamental information for the development of a male contraceptive and treatment of certain forms of male infertility.