Role of C-4 pathway in crustacean chloride cell function.

A hypothetical model for the bioenergetic regulation of ion transport in the chloride cell of the larval crustacean salt gland is presented. Current data dealing with the ultrastructural, electrochemical, and biochemical events associated with cytodifferentiation of the crustacean (Artemia salina) salt-excreting epithelia is compiled and tabulated. A C-4 dicarboxylic aicd pathway is postulated to serve as a facultative anaerobic shunt to meet the demands of the high rate of glycolysis required by salt-secreting epithelium. This mechanism involves the fixation of CO2 from exogenous bicarbonate while forming net amounts of metabolic water and high energy nucleotide equivalents from stored diGDP.