Impaired insulin secretion of aging: Role of renal failure and hyperparathyroidism

Impaired insulin secretion of aging: Role of renal failure and hyperparathyroidism. Available data indicate that insulin secretion is impaired with aging. Almost all the studies that examined insulin secretion by old animals did not take into consideration the state of renal function or the blood levels of parathyroid hormone (PTH). Old animals may have chronic renal failure (CRF) and secondary hyperparathyroidism, and both of these conditions impair insulin secretion. It is possible, therefore, that the impaired insulin secretion of aging is not due to old age per se , but rather to associated CRF and excess PTH. The present study examined this issue in adult (6 month old) and senescent rats (2 years old) with and without CRF and excess PTH. Senescent rats without CRF had normal renal function and normal blood levels of PTH, and the values were not different from those observed in adult rats. Creatinine clearance in senescent rats with CRF was significantly (P per se , but is due to the associated CRF and secondary hyperparathyroidism that develops in many, but not all old animals. Our results indicate that studies examining the effect of aging on body function should take into consideration the level of renal function and of the serum PTH, since both CRF and excess PTH adversely affect the functional integrity of many organs.