DIURNAL variations have been noted to occur in numerous bodily functions.1-4 The observation of high blood sugars drawn after lunch in persons with normal glucose tolerance made us question whether a diurnal variation occurs in glucose tolerance. Roberts5 has repeatedly stated that there is such a variation. Hayner and Francis,6 on the other hand, concluded from their population study that there was no diurnal variation in glucose tolerance. It seems important to determine definitely whether a diurnal variation in glucose tolerance does occur since, heretofore, little attention has been paid to the time of day tests are given in detection drives and population studies. The purpose of this study was to determine whether a constant glucose load elicits a variable response at different times of day.
Certain problems are inherent in the study of any function which undergoes circadian or diurnal variation. This is especially true when