Effect of gestational diabetes on insulin receptors in human placenta.

The aim of this work was the characterization of insulin binding to a partially purified preparation of plasma membranes from gestational diabetic placenta in order to establish a comparison with normal pregnancy. A decrease in the number of insulin receptors per mg protein in placenta from gestational diabetic mothers was found. Comparable inhibitory effects of unlabelled insulin suggest that the binding affinities were similar in both groups of patients. The ability of the placental preparation to degrade 125I-insulin was not significantly different in both situations. The existence of a negative feed-back regulation of the insulin receptors in placental membranes was suggested by the fact that plasma insulin levels were significantly higher in the gestational diabetic mothers.