Effect of aging on glucose tolerance in spontaneously hypertensive rats

We studied the age-related changes of glucose tolerance in female spontaneously hypertensive rats (SHR) that did not become obese with aging. Oral glucose tolerance test was performed in young (3 months), middle-aged (6 to 11 months), and aged (26 months) SHR. Fasting plasma glucose was significantly lower in aged SHR than in young SHR. The increase in plasma glucose after glucose administration over fasting level was significantly higher in aged SHR than in middle-aged SHR, but did not differ between young and aged rats. Pancreatic islet size and pancreatic immunoreactive insulin content were similar between young and aged SHR. The present study demonstrated that glucose tolerance did not deteriorate in SHR with aging, while genetic hypertension persisted. This suggests that the persistence of hypertension per se may not affect glucose tolerance in SHR.