Physiological and clinical aspects of circadian variations in glucose tolerance.

Significance of the circadian periodicity in glucose tolerance has been presented from physiological and clinical points of view in mechanisms responsible for this periodicity of which afternoon glucose intolerance is most evident. In healthy subjects, circadian fluctuations in insulin secretion and in sensitivity to insulin at tissue level are dominating. Circadian oscillations in insulin response to a glycemic stimulus as well as inherent periodicity in activity of the beta cells have been demonstrated by many authors.