Features of Endocrine Function of the Pancreas with Aging in Nonhuman Primates with Various Types of Adaptive Behavior

An increasing number of works study the relationship of mental disorders, such as depression and anxiety, with the risk of developing type 2 diabetes mellitus. However, there are practically no publications on the study of the relationship of the features of higher nervous activity, particularly adaptive behavior, in healthy individuals with the risk of developing age-related dysfunction of the pancreatic islet apparatus (PIA). The purpose of this study was to investigate features of the functioning of the PIA during aging in individuals with normal standard behavior (SB), as well as anxiety- and depressive-like behavior (DAB) in experiments on nonhuman primates. The study involved 76 physically healthy young mature and old female rhesus monkeys with SB and DAB. Old animals were divided into subgroups with normal (NW) and excess (EW) body weight. All young animals were characterized by NW. The function of PIA was assessed with a glucose tolerance test. Intergroup differences were seen in the functioning of the PIA in young animals with DAB, which was characterized by signs of impaired early insulin response, apparently due to a decrease in the sensitivity of β-cells of the pancreas to glucose. With aging, the function of the PIA was damaged in all animals, but the features of its changes depended on both the affiliation to a particular behavioral group and the animal’s body weight. With aging in animals with SB, the development of relative insulin resistance of peripheral tissues was observed, accompanied by impaired glucose tolerance and a compensatory increase in the secretory activity of the PIA, which were more pronounced in animals with EW. The age-related dysfunction of the PIA in animals with DAB and NW was similar to age-related changes in the PIA function in animals with SB and NW. At the same time, aging animals with DAB and EW showed a more significant peak glucose concentration than that for old animals with SB and EW, accompanied by the minimum “disappearance” rate of glucose from the circulation and significantly lower insulin secretion than that in animals with SB and EW. Thus, the age-related dysfunctions of the PIA in primates with SB and DAB are unidirectional upon the development of insulin resistance, impaired glucose tolerance, and a compensatory increase in insulin secretion; however, in old animals with DAB and EW, they are accompanied by exhaustion of the PIA function and increased risk for type 2 diabetes mellitus.