Oral glucose tolerance test in the cynomolgus monkey (Macaca fascicularis)

The glucose tolerance test was simplified so that it could be performed on more than one cynomolgus monkey (Macaca fascicularis) at a time. Glucose was administered orally in a dose of 2 g/kg body weight as a 50% aqueous solution, and blood samples were taken just before and 30 minutes and 150 minutes after glucose administration. The simplified test was conducted on a total of 93 cynomolgus monkeys. Glucose tolerance curves obtained by this method were classified into three patterns with regard to the increasing rate of serum glucose concentration per minute and the decreasing rate. Seventy-one monkeys showed the first pattern characterized by an increasing rate of 1.0 mg/min or more and a decreasing rate of 0.2 mg/min or more. The second pattern showing an increasing rate of 1.0 mg/min or more and a decreasing rate of less than 0.2 mg/min was obtained with 10 monkeys. The remaining 12 monkeys exhibited the third pattern in which the increasing rate and the decreasing rate were less than 1.0 mg/min and 0.2 mg/min, respectively. The first pattern is considered to be normal glucose tolerance, while the second and third patterns are regarded as abnormal ones. The incidence of the abnormal patterns was significantly higher in wild-imported cynomolgus monkeys than in laboratory bred monkeys.