Metabolic rates of vascular endothelial cellsin vitro.

Cultures of endothelial cells and cell lines of endothelial origin were maintained at confluence without medium exchange for a period of 72 h. During this time period the concentration of nutrients - amino acids and glucose - and metabolic waste products - lactate and ammonium - was determined as well as cell vitality and cell numbers. Metabolic rates were calculated and compared for the different cell lines. Surprisingly the primary cells showed significantly higher rates of glucose and glutamine consumption, respectively lactate production than the immortalized cell lines. Except for one tumorigenic cell line all cells showed a significant participation of transaminases in glutamine/ammonium metabolism. Furthermore it could be shown that in routine culture there was no depletion of nutrients or critical accumulation of ammonium or lactate over a culture period of 72 h.