Abstract
Circadian rhythm of the glucose, insulin and incretin concentrations had been reported in humans study. However, it is unclear in dogs. Therefore, the purpose of this study is to compare the blood glucose, insulin and incretin levels between day- and night-time in healthy dogs. For data analyses, day-time was defined as 7:00 am-7:00 pm and night-time as 7:00 pm-7:00 am. Four healthy dogs were used in this study and fed the same amount of diets twice a day（semidiurnal）. We measured postpandial glucose, insulin and incretin（glucose-dependent insulinotropic polypeptide〔GIP〕and glucagon-like peptide-1〔GLP-1〕）, concentrations. No significant changes in mean glucose concentrations, at different time points, were observed between day- and night-time. Meanwhile, significant increase was observed in postprandial insulin concentration at 1 hr of night-time compared to that of day-time. Postprandial GIP and GLP-1 concentrations were increased in a few hours, and followed by gradually decreased. However, different higher peak concentrations were observed between the day-time and the night-time. These results suggested that circadian rhythm of these parameters were also found in healthy dogs.
