Estriol Modification of the Effects of Progesterone and Human Chorionic Somatomammotropin on Glucose Tolerance and Plasma Insulin in Rhesus Monkeys

The effects of estriol and estradiol on progesterone-induced changes in glucose and insulin metabolism have been studied in mature female rhesus monkeys. The addition of striol to treatment regimens containing progesterone only or human chorionic somatomammotropin (HCS) plus progesterone resulted in improvement in mean glucose disappearance rates following intravenous glucose administration without significant changes in the mean total insulin responses to glucose. This change in glucose tolerance was primarily due to apparent improvement in peripheral glucose utilization rather than any increment in total or initial insulin responses to glucose. By contrast, the addition of estradiol to the progesterone treatment regimen produced no changes in the mean glucose disappearance rate or the plasma insulin response to glucose, although there was an increase in mean fasting glucose and insulin concentrations after estradiol + progesterone treatment. These results indicate that estriol and estradiol have different effects on glucose and insulin metabolism and suggest that estriol may modify the diabetogenic tendencies of progesterone and HCS during primate pregnancies.