Energy and heat production of human erythrocytes in different media

Variation in ATP consumption of human erythrocytes was achieved by incubation in different media. Addition of ouabain to a conventional isotonic medium or elimination of the ionic Na+-K+ gradient across the membrane decreases lactate production of the cells by about 40%. Applying a calcium-gradient of 1 mmol . l-1 across the membrane increased glycolysis by about 25%. The various introduced changes in the medium and thus in ATP-consumption cause similar alterations in heat production and lactate production. The experimental results give no suggestions explaining the origin of the part of the heat production that is unrelated to glycolysis.