Prevention of hypo‐osmotic swelling by detergents provides clues to the membrane structure of rat sperm

The proportion of sperm from the caput epididymidis of the rat that swelled in hypo-osmotic media was reduced in a dose-dependent manner by detergents, with relative effectiveness as follows: CTAB greater than Digitonin greater than Hyamine 10-X greater than SDS greater than Triton X-100 greater than Deoxycholate. Polymyxin was a poor lytic agent, possibly because anionic lipids are in the inner leaflet of the membrane. Less digitonin was needed to lyse mature sperm from the distal cauda epididymidis, suggesting that there is less cholesterol in their membranes.