STUDIES ON CARBOHYDRATE AND FAT METABOLISM IN THE LUNG

Abstract

Normal subjects and patients with heart diseases, chronic pulmonary emphysema and other chronic pulmonary diseases were selected for this study. Samples of blood were taken simultaneously from pulmonary artery (mixed venous blood) and brachial artery (arterial blood) at rest, in anoxic state and under other conditions. Glucose, lactic acid, pyruvic acid, serum lipoprotein index, total serum cholesterol and serum phospholipid were checked up. Cardiac output was also measured by Fick as well as dye dilution methods. Carbohydrate and fat metabolism in the lung was studied from the aspects of the arterio-venous differences of the blood substances stated above, and the differences of values of cardiac output determined by two different methods (Fick and dye) were also studied from the standpoint of O2 consumption in the lung tissue. 1) Ratio of two values of cardiac output determined respectively by Fick method and dye dilution method was higher in the chronic pulmonary diseases than in the non-pulmonary diseases. 2) But there was not statistical significance in the arterio-venous differences of glucose, lactic acid and pyruvic acid at rest in general, including non-pulmonary diseases and pulmonary diseases. 3) In the chronic emphysema lactic acid showed higher concentration in the arterial blood than in the mixed venous blood and glucose had a tendency to show higher concentration in the mixed venous blood. 4) During exercise the concentration of lactic acid was decreased after the passage of the lung, and the concentration of glucose and pyruvic acid showed the same tendency to be decreased. But during IPPB/I using room air and during inhalation of 100% O2 or anoxia test, any significant changes were not observed in the concentrations of these 3 substances. 5) The ratio of coefficients of changes in cardiac output by Fick method and dyedilution method produced by exercise seemed to be higher than the ratio of coefficients of changes produced by the other conditions stated above. 6) Serum lipoprotein index and the concentration of total serum cholesterol were increased after the passage of the lung, and on the contrary they were decreased after the passage of myocardium.