Studies on the metabolism of semen. 4. Aerobic and anaerobic utilization of fructose by spermatozoa and seminal vesicles

Abstract

The process of fructolysis plays an essential role in the survival of mammalian spermatozoa (from man, bull and mouse) both under anaerobic and aerobic conditions. Anaerobic fructolysis provides the main source of energy for spermatozoa. Aerobically, both fructose and lactic acid function by prolonging and maintaining the sperm respiration. In buffered sperm suspensions fructolysis continues at a steady rate, and follows a linear course until practically the entire sugar content has been exhausted. The rate of fructolysis is greater under anaerobic than aerobic conditions. Excessive dilution of sperm suspensions causes a decrease in the rate of both fructolysis and respiration. By using a suitably chosen concn. of NaF, it is possible to abolish fructolysis completely while the respiration is only partly suppressed. Under such conditions it was found that the spermatozoa were immotile even although there was still some O2 consumption. Spermatozoa washed free from fructose-containing seminal plasma can utilize anaerobically to the same extent added fructose or glucose. In this respect the sperm cells differ from the fructose-producing tissue, the seminal vesicle, which utilizes glucose anaerobically, but not fructose. Aerobically, however, both sperm and the seminal vesicles are capable of metabolizing both fructose and glucose.