Metabolic consequences of the early onset of obesity in common marmoset monkeys

OBJECTIVE: We assess the common marmoset as a model of early obesity. We test the hypotheses that juvenile marmosets with excess adipose tissue will display higher fasting glucose, decreased insulin sensitivity, and decreased ability to clear glucose from the blood stream. DESIGN AND METHODS: Normal and Obese (body fat > 14%) common marmoset infants (N = 39) were followed from birth until one year. Body fat was measured by quantitative magnetic resonance. Circulating glucose was measured by glucometer; insulin, adiponenctin and leptin by commercial assays. The QUICKI (a measure of insulin sensitivity) was calculated for subjects with fasting glucose and insulin measures. Oral glucose tolerance tests were conducted at 12 months on 35 subjects. RESULTS: At 6 months Obese subjects already had significantly lower insulin sensitivity (mean QUICKI = .378±.029 versus .525±.019, N=11, p=.003). By 12 months Obese subjects also had higher fasting glucose (129.3±9.1 mg/dL versus 106.1±6.5 mg/dL, p=.042) and circulating adiponectin tended to be lower (p=.057). Leptin was associated with percent body fat; however, birth weight also influenced circulating leptin. The OGTT results demonstrated that Obese animals had a decreased ability to clear glucose. CONCLUSIONS: Early onset obesity in marmosets results in impaired glucose homeostasis by one year.