Plasma Insulin Response and Glucose Tolerance in Pregnant Rhesus Monkeys

Glucose tolerance and plasma levels of immunoreactive insulin were studied in 11 rhesus monkeys in the third trimester of pregnancy. The tests were repeated between 2 and 3 weeks postpartum. In pregnancy, statistically significant increases were found in fasting insulin levels and insulin response to iv glucose infusion. There were no significant differences in plasma glucose and glucose tolerance. These findings of fasting hyperinsulinemia and enhanced insulin response to glucose are similar to those reported in humans and are probably the result of placental lactogen and/or progesterone. (Endocrinology86: 435, 1970)