Adiponectin has a crucial role on the function, proliferation and viability of β-cell via action of two receptors; AdipoR1 and AdipoR2, but age related change of adiponectin system genes in pancreas is unclear or controversial. This study sought to investigate the effects of aging on serum adiponectin levels, adiponectin and its receptor expression in the rat pancreas in aging process.
In this experimental study, insulin resistance markers including serum insulin and glucose concentrations, homeostatic model assessment of insulin resistance (HOMA-IR), oral glucose tolerance test (OGTT), glucose induced insulin secretion (GIIS), serum adiponectin levels and pancreatic expression of adiponectin and its receptors were studied in male Sprague-Dawley rats at the age of 2, 5, 10, 18, 52 and 72 week of age.
We found that aging triggered signs of insulin resistance characteristics in rats at 72 age week including marked insulin reduction, hyperglycemia and increased HOMA-IR. Circulating adiponectin, and pancreatic expression of adiponectin and AdipoR1 was gradually decreased with age, while the opposite expression pattern of AdipoR2 was observed in old rats.
Because adiponectin and adiponectin signaling have crucial role in β-cell function and viability, we concluded that reduction of adiponectin signaling may be involved in aging induced β-cell dysfunction. As a results, manipulation of adiponectin signaling may be a beneficial approach for improvement of β-cell function in age people.