Figure 2.

(upper part): Plasma insulin and blood glucose responses after meal ingestion during the light period and dark period in animals on a regular feeding regimen of 6-meals-a-day. Before sampling animals had been on this regimen for 2–3 weeks. Boxes indicate meals. Despite similar meals (3.1 ± 03 g) and comparable glucose increments insulin responses significantly differ depending on the time of day. (lower part): Plasma glucose and insulin responses after the intravenous injection of a glucose bolus (500 mg/kg BW) at different times of the light/dark cycle. The maximal glucose increment at ZT14 was significantly lower than the ones at the other 5-time points. On the other hand, the total amount of insulin released did not differ between the different time points. Responses are expressed as the difference from the respective t = 0 values. Black bars indicates meals in the dark period. ZT = Zeitgeber Time; ZT12 being defined as the onset of the dark period. Adapted from Ref. [57] (upper figure) and Ref. [60] (lower figure).