Gastrointestinal hormones and cortisol in normal pregnant women and women with gestational diabetes.

In pregnancy the secretion of a number of gastro-enteropancreatic hormones is considerably altered. These changes might be involved in the gestational modification of gastrointestinal physiology. The enteral stimulation of insulin secretion (the incretin effect) is diminished in pregnancy--both when determined indirectly and when the gastric inhibitory polypeptide (GIP) response to glucose ingestion is considered. Whether this is important for the deterioration of glucose tolerance in pregnancy is uncertain. In gestational diabetics similar findings as in normal pregnant women were obtained except that the GIP response to glucose ingestion was smaller and the GIP response to lipid ingestion greater than in normal women. It is, however, unlikely that these differences are responsible for the development of gestational diabetes. Significant positive correlations were found between the increase of plasma cortisol levels during normal pregnancy and the concomitant decrease in glucose tolerance indicating that the increased cortisol levels might be involved in the development of the insulin resistance found in normal pregnancy.