Carbohydrate impairment and insulin secretory abnormalities among Macaca mulatta from Cayo Santiago

Rhesus macaques (Macaca mulatta) from Cayo Santiago were examined for evidence of carbohydrate intolerance indicative of potential development of non-insulin-dependent diabetes mellitus (NIDDM). Monkeys 6 to >20 years from natal Groups J, M, and P, an AGED Group (all >20 years), and unrelated monkeys removed from the island in association with other groups (CAYO), were examined with intravenous glucose tolerance tests (iv-GTT). Morphometric measurements were made on all tested monkeys. Impairments included fasting hyperglycemia (>115 mg/dl), impaired glucose clearance (K <2.0%/min), fasting hyperinsulinemia (>150 μU/ml) or hypoinsulinemia (<20 μU/ml), and insulin secretory abnormalities (>500 μU/ml or <75 μU/ml). Natal groups J and M had 31% with impairments, group P had 0% the AGED group had 45%, and the CAYO group had 33%. Impaired glucose clearance was usually attributable to a reduced insulin response. Impairments correlated significantly (p ⩽ 0.05) to body weight and a modified Quetelet index, but not to sex, acute stress, or islet cell antibodies; the relationships to age could not be delineated in this survey. Impairements in monkeys are indicative of various stages in the asynchronous development of carbohydrate intolerance leading to NIDDM.