Influence of substrate composition on vitro oxygen consumption of lung slices

Abstract

The endogenous oxygen consumption of lung, liver and spleen slices is only slightly increased by glucose in an SRP medium compared with its effect on heart and kidney slices. Individual substrates which induced a highly significant increase in oxygen uptake of lung tissue were succinate, acetate, pyruvate and glucose, whereas citrate and fumarate gave a non-significant response. When glucose and a-ketoglutarate were simultaneously used as substrates the rate of oxygen uptake was significantly higher than with glucose alone. Acetate, pyruvate and gluta'mate in combination with glucose had no significant effect. Acetate and succinate in combination with pyruvate induced a significantly higher rate of oxygen uptake than pyruvate alone. The changes observed with pyruvate + aketoglutarate and pyruvate + citrate were not significant. Albumin complexes of palmitate, stearate and ,a-hydroxybutyrate did not affect the endogenous oxygen uptake. Similarly, these complexes in combination with carnitine had no stimulating effect. However, fatty acid complexes in the presence of adenosine triphosphate (ATP) gave a highly significant increase, followed by a further increase in oxygen uptake when a combination of ATP and carnitine was used.

S. Afr. Med. J., 48, 1882 (1974).