Kinetics of elimination of glucose from the blood during and after a continuous intravenous injection.

The glucose tolerance tests in routine clinical use are predominantly of the oral type, in which the sugar is administered by mouth. Such tests, however, suffer from the disadvantage that the rate of intestinal absorption has an effect on the results, and its variations may entirely overshadow any possible changes in carbohydrate metabolism. This difficulty may, of course, be obviated by administering the sugar by vein, and intravenous tolerance tests have actually been used by many workers (1-8) .2 In these tests the sugar has generally been given as a single rapid injection. While such a method undoubtedly gives useful information, it can hardly be regarded as a quite physiological one. A more natural procedure would be to inject glucose slowly over a long period of time, thus imitating the normal process of absorption. So far, tolerance tests of this type have apparently received scant attention. As it seemed that this method might provide additional information not easily obtainable from the tests based on a single rapid injection, we decided to carry out the following experiments, in which glucose was administered as a continuous injection of constant rate and of relatively long duration.