Effect of diet restriction on glucose metabolism and insulin responsiveness in aging rats

Abstract

The effect of age and of prolonged caloric restriction on glucose tolerance and insulin responsiveness has been studied in male Fischer 344 rats. Beginning at 1 month of age dietary intke of an experimental group (R) was limited to 60% of that of the control group (AL) which was allowed to eat ad libitum. Studies were carried out at intervals up to 24 months of age. In AL rats the oral glucose tolerance curve showed progressively higher peak levels of plasma glucose with age, and a decrease in the plasma insulin concentration at the time of the glucose peak. The R group did not show the increase in peak value with age and the corresponding insulin concentration was lower than that of the AL group. These results are compatible with a delay in the first phase of insulin secretion in aging AL rats.