@article {10.3844/ajassp.2009.1854.1859, article_type = {journal}, title = {Oxidation of Exogenous Lactate by Lactate Dehydrogenase C in the Midpiece of Rat Epididymal Sperm is Essential for Motility and Oxidative Activity}, author = {Yamashiro, Hideaki and Toyomizu, Masaaki and Kadowaki, Akane and Takeda, Zenya and Nakazato, Fumiaki and Toyama, Natsuki and Kobayashi, Jin and Sato, Eimei}, volume = {6}, year = {2009}, month = {Oct}, pages = {1854-1859}, doi = {10.3844/ajassp.2009.1854.1859}, url = {https://thescipub.com/abstract/ajassp.2009.1854.1859}, abstract = {Problem statement: To identify the metabolic reaction-glycolysis or oxidative phosphorylation that is mainly involved in the production of energy required for rat sperm mobilization. Approach: Epididymal sperm were collected from Wistar rats and extended in lactate-containing or lactate-free raffinose-modified Krebs-Ringer Bicarbonate solution (mKRB)-egg yolk medium supplemented with 0, 1, 2, or 3 mM 2-Deoxy-D-Glucose (2 DG) and 1, 2, or 3 mM sodium Oxamate (OX). Sperm motility, straight-line velocity (VSL) and oxygen consumption were evaluated. Further, immunofluorescent localization of Lactate Dehydrogenase C (LDH-C) in sperm was also performed. Results: Low concentrations of 2DG (1 and 2 mM) did not significantly affect motility, VSL and oxygen consumption of sperm extended in the lactate-containing medium. While sperm motility and oxygen consumption were significantly inhibited by even 1mM 2DG in sperm extended in lactate-free medium. Sperm motility significantly inhibited in the case of sperm extended in lactate-containing and free-medium with 1 mM OX. We also found that sperm motility was not maintained in the absence of lactate throughout the 3 h incubation period. Immunofluorescence study revealed that mainly LDH-C was may be localized in the intramitochondrial region of the sperm. Conclusion: These results suggest that exogenous lactate enhances lactate oxidation by LDH-C, thereby promoting mitochondrial oxidative reactions in the midpiece and maintaining the mobilization of rat epididymal sperm.}, journal = {American Journal of Applied Sciences}, publisher = {Science Publications} }