Metabolism of Glycerol, Sorbitol and Related Compounds by Spermatozoa

Abstract

THE finding that the addition of glycerol to semen increases considerably the proportion of spermatozoa which survive freezing and storing at − 79°C.^1,2 opened up the question as to whether or not glycerol can be metabolized by the intact sperm cells. Early-experiments indicated that, unlike certain glycolysable sugars and organic acids, glycerol, in common with other alcohols, has no marked initial-rate preserving effect on the sperm respiration³, and exerts its action mainly through a protective influence on sperm colloids, probably owing to its high electrolyte- and water-binding capacity^4,5. More recent investigations, however, have shown that although glycerol does not affect sperm motility and respiration in a diluent containing fructose, it increases markedly the oxygen consumption of washed sperm suspensions, giving rise at the same time to significant quantities of lactic acid⁶. It has also been demonstrated that glycerol labelled with radioactive carbon enters spermatozoa in measurable amounts; sperm cells separated from the seminal plasma showed a higher uptake and. utilization of glycerol than did spermatozoa in the presence of seminal plasma⁷. The present study was undertaken to investigate : (1) the relationship between glycerol disappearance and lactic acid formation ; (2) the behaviour of compounds related to glycerol such as dihydroxyacetone and phosphoglycerol. Glycerol was determined colorimetrically⁸, and the other methods used were those described earlier⁹.