Studies in carbohydrate metabolism in the rabbit

Abstract

(1) A new and reliable method has been found for the estimation of fructose in blood, which is not interfered with to any great extent, by glucose. It is suggested that this method might prove to be a valuable aid in the elucidation of further facts bearing on the utilisation of fructose in the intact animal.

(2) This method has been employed to follow the fate of ingested and injected fructose in rabbits.

(3) The results obtained suggested that fructose was as efficient, if not more so, than glucose in stimulating the secretion of insulin.

(4) This conclusion was tested by studying the blood sugar curves obtained after ingestion of glucose, and comparing them, with curves obtained after a similar oral dose of glucose was followed by an injection of fructose.

(5) The conclusion that fructose was more effective, in this direction, than glucose was tested by comparing the curves obtained above, with curves given after oral ingestion of glucose was followed by intravenous injections of glucose.

(6) These results and the work of other authors suggest the hypotheses: that conversion to glucose does occur slowly in normal animals; that the takes place is the liver (although some evidence is given indicating that other tissues can effect the same change); that this conversion, of fructose to glucose, is independent of insulin; and that direct synthesis of glycogen from fructose does not occur.

(7) This theory is discussed in relation to the work of other authors.