The effect of reaction changes on human carbohydrate and oxygen metabolism

Abstract

Since changes of hydrogen ion concentration affect reactions catalyzed by the enzymes of the body in vitro, they may be expected to do so in vivo. But as it is impossible to change the reaction of the tissues without altering the concentration of other ions than hydrogen, caution is required in interpreting the results. In the experiments here reported the cH of our tissues was increased by breathing carbon dioxide and drinking ammonium chloride solution, diminished by over-breathing and sodium bicarbonate ingestion, as described by us in a former paper (1). If the same results are produced by two such different methods of increasing or diminishing the cH, they probably spring from this change as common cause; if not, they are probably due to other causes. Methods . Blood sugars were estimated by Bang’s (2) original method. The relation between rotatory and reducing power of the blood sugar before and after hydrolysis was determined for us by Smith and Winter by their method (3). Acetone, aceto-acetic acid and β-oxybutyric acid were determined by Lublin’s (4) method. This proved quite satisfactory for acetone and acetoacetic acid, but it was found that normal urines on heating with potassium bichromate and sulphuric acid gave a small yield of bodies reducing iodine in alkaline solution. However, if (as is probable) the excretion of these per hour remained fairly constant, the correction to be made for their presence was small. Benedict’s (5) solution was used as a qualitative test for sugar in urine. Respiratory metabolism was determined by the method of Douglas (6) after at least half-an-hour’s moderate rest, and 10 minutes’ complete rest in a deck chair, during the last five of which the subject breathed through valves. Fasting metabolisms measured in this way on two days were 1⋅54 and 1⋅57 calories per minute, the corresponding basal values being 1⋅43 and 1⋅47, or 7 per cent. lower. The calorie values of the oxygen are calculated from Carpenter’s (7) tables, neglecting protein metabolism, and the error due to changing CO 2 capacity of the body.