Voltage-dependent anion channels (VDACs) are found in the outer mitochondrial membrane of all eukaryotes. They are small (30kDa) channel proteins that are involved in the translocation of metabolites and are sometimes also referred to as mitochondrial porins. There are three mammalian Vdac genes encoding VDAC1-3 proteins (Decker et al., 1999; Sampson et al., 1997). Targeted mutation of Vdac3 causes male infertility (Sampson et al., 2001). Normal numbers of spermatozoa are produced but motility is decreased (approximately 25% of wild type). The mutant mice also have defects in oxidative phosphorylation in skeletal muscle. Electron microscopy revealed structural defects in two thirds of the sperm axonemes; often the loss of a single microtubule doublet. The defect was rarely observed in testicu-lar sperm but developed with maturation of the sperm in the epididymis. These mice demonstrate that functional mitochondria are required for the correct formation of the axonemes with resultant effects on sperm motility and fertility.
Was this article helpful?
Far too many people struggle to fall pregnant and conceive a child naturally. This book looks at the reasons for infertility and how using a natural, holistic approach can greatly improve your chances of conceiving a child of your own without surgery and without drugs!