DIURNAL VARIATION IN THE BLOOD-SUGAR AND PLASMA-INSULIN RESPONSE TO TOLBUTAMIDE

Twenty subjects were given intravenous tolbutamide on two occasions, once in the morning and once in the afternoon. The fall in blood-sugar was significantly less in the afternoon. The rise in plasma-insulin was also less in the afternoon, but this difference was not statistically significant. It is suggested that a diurnal change in sensitivity to endogenous insulin contributes to the difference in blood-sugar response.