Galactose and glucose tolerance in normals, the obese, and post-gastrectomy patients.

The interpretation of oral glucose tolerance tests is complicated by varying individual rates of absorption from the intestinal tract. Intravenous tests eliminate the absorption factor, but there is evidence that they may be less sensitive than oral tests in detecting impaired tolerance (Moyer and Womack, 1950). It was considered that a galactose tolerance test performed in parallel with a glucose tolerance test would indicate the rate of absorption of glucose, since there is evidence that galactose and glucose are absorbed similarly but differ in the manner of removal from the blood. The rates of absorption of galactose and glucose are independent of the amount of sugar present once a certain concentration is reached (Cori, 1925; Groen, 1937). When a mixture of the two sugars is given, the total maximum rate of absorption of the two together approximates the maximum rate of absorption of either when given alone (Cori, 1926). The actual rate of absorption of galactose is slightly greater than that of glucose, the ratio 110: 100 being reported by Cori (1925) in rats and 118: 100 by Groen (1937) in man. No other sugar shows a rate of absorption so closely resembling that of glucose. Fructose is absorbed at half the rate, and " unphysiological sugars," such as rham-nose and xylose, at one-tenth of the rate of glucose