METABOLIC STUDIES ON THE MICROPINOCYTIC PROCESS IN ENDOTHELIAL-CELLS

Tufts of capillary endothelium isolated from rat epididymal fat ingest [14C]sucrose by the process of micropinocytosis. Ingestion of sucrose for periods in excess of 30 min was quantitated using the concentration of cellular DNA as a standard. Capillaries incubated in the metabolic inhibitors 2,4-dinitrophenol, NaN3, or iodoacetate exhibit a dose-dependent reduction of cellular ATP. Micropinocytic ingestion of [14C]sucrose is not affected by concentrations of these inhibitors which markedly reduce or deplete ATP pools. Pure oxygen or nitrogen atmospheres also have no effect on micropinocytosis. Ingestion of [14C]sucrose is reduced, however, at temperatures lower than 37° or in the presence of Zn2+. © 1979.