Response to glucose loading of the lean squirrel monkey in unrestrained conditions

The response of blood glucose (BG), free fatty acids (FFA), and insulin (IRI) to both intravenous (IVGTT) and oral (OGTT) glucose tolerance tests was evaluated in unrestrained, permanently catheterized squirrel monkeys. The mean glucose assimilation rate (K value) for 25 IVGTT was 7.75 +/- 2.84. FFA maximally decayed 54 percent from a mean basal of 1,008 +/- 221 mueq/l associated with a onefold increment inIRI from basal (7.5 +/- 3.5 muU/ml) at 2-5 min. No significant changes were found during intravenous saline loading alone. OGTT (4g/kg) produced peak BG levels at 15-30 min with an immediate FFA decrease of 63 percent and a onefold IRI increment. Carcass composition analyses from 17 animals showed a total extractable lipid content of 6.2 percent. The K value, significantly higher than previously reported, appears to fit well with that expected for the species. The rapid decrease in FFA and BG concentrations demonstrate an apparent high efficiency of a low IRI increment. The association of the low IRI after loading with a low triglyceride depot is discussed.