Energy metabolism and spermatogenesis

Infertility has become a significant health burden around the globe as it is believed that 15 % of married couples struggle with infertility, with half of the problem accrued to the male. The issue of male infertility could be traced to insufficient or absence of spermatozoa. Glucose metabolism is essential for continued spermatogenesis and for the reproductive potential of sperm cells. Appropriate nutrition is critical in maintaining reproductive function as caloric restriction along with weight reduction, excessive food consumption and obesity are harmful to reproductive function. The link between metabolism and reproduction is tied to metabolic hormones like insulin, leptin and thyroid, extracellular environment, mitochondria function, nutrient substrate, availability, and environmental stressors. Although matured spermatozoa utilize glucose directly, it is not the preferred energy substrate for germ cells as they rely on Sertoli cells to supply lactate. The reproductive potential of sperm cells depends on certain modifications like hyperactivated motility, which is mainly dependent on glucose metabolism. Without other energy sources, spermatozoa utilize their internal lipid stores. The uptake and metabolism of glucose by sperm are essential endpoints for determining the potential fertility of male individuals. The biological energy in sperm cells fuels all the physiological processes they engage in, from their deposition in the female reproductive tract to the point where they fertilize an egg. This article thus reviews facts pertinent to the energy metabolism of male germ cells and Sertoli cells.