Carbohydrate and Adenosinetriphosphate in Sea-Urchin Semen

Abstract

SEA-URCHINS differ from mammals, in which fertilization is internal and the survival of spermatozoa largely depends on extraneous nutrients provided by accessory secretions, in that fertilization takes place after the eggs and sperm have been shed into sea water, which is a poor source of organic nutrients. Furthermore, unlike mammalian spermatozoa which in most species, including man, obtain their metabolic energy through anaerobic and aerobic glycolysis¹, sea-urchin spermatozoa depend on a non-glycolytic and strictly aerobic metabolism; sea-urchin semen is devoid of significant amounts of fructose or other fermentable sugars; and the spermatozoa are incapable of glycolysing sugars added in vitro².