Study of response to continuous intravenous injection of large amounts of glucose

Abstract

Realizing that no isolated series of observations, such as blood sugar curves, the degree of glycosuria, the gas exchange nor the tissue analysis, is adequate in itself as a measurement of carbohydrate capacity, an attempt has been made to ascertain the response elicited by intravenous injection of glucose continuously for several hours, by means of simultaneous studies of blood sugar, hemoglobin, pH and CO₂ content of plasma, urine volume and sugar, respiratory quotient and heat production. The method of study differed from that of Woodyatt and others in that more factors were correlated, larger amounts of sugar were administered, and the recovery period was observed for several hours. Unanesthetized dogs on standard diet were used. The method of administration was essentially the same as employed by Woodyatt. 1 Glucose in 30 per cent solution was given at the rate of 4 gm. per kilo per hour. Indirect calorimetry was used to measure gas exchange.

It was found that under similar conditions, the response of the same dog to the standard injection on various occasions was remarkably uniform throughout. Values from different dogs were in fair agreement.

Sugar rapidly left the blood, 80 per cent to 100 per cent disappearing as rapidly as injected. There was usually a peak in the blood sugar concentration curve during the first half hour, after which the divergence was considerable, varying more in different dogs than in the same animal. After injection there was a rapid return to normal limits requiring only 1/2 to 1 hour. In some cases distinct hypoglycemia ensued.

Hemoglobin fell moderately during the injection, soon returning to normal following its close. Fluctuations in pH were slight, never exceeding 0.1, and usually less than 0.05. Carbon dioxide content usually fell.