The metabolism and localization of glycerol by bovine spermatozoa

Abstract

Since the discovery that glycerol, a trihydroxy alcohol, would provide protection for spermatozoa during the freezing and thawing process, many questions have arisen concerning its metabolism and mode of action. Most of the recent work, with various types of single cells ans tissues, has shown that the cells are permeated by glycerol and that entry must occur before full protection is afforded. However, the methods employed in the majority of these studies have not proven successful for bovine spermatozoa, possibly due to its extremely inflexible cellular membrane and/or the slow rate at which glycerol enters the cell. The majority of the information concerning glycerol entry into bovine spermatozoa bas been supplied by metabolic studies. These studies have indicated that glycerol is metabolized by spermatozoa both anaerobically and aerobically in quantities too large to attribute the action to extracellular enzymes alone. However, relatively little information is available concerning the intracellular loci of glycerol action. Thus, this investigation was undertaken to provide additional information concerning the metabolism and localization of glycerol in the bovine spermatozoa.