Maternal plasma leptin levels and their relationship to insulin and glucose in gestational-onset diabetes.

To investigate the changes in leptin levels and the relationship between this substance and insulin and glucose in pregnant women with gestational-onset diabetes, we measured plasma leptin levels in the maternal peripheral vein of 17 healthy and 17 diabetic women at 29 and 33 weeks of gestation. We also correlated maternal plasma leptin levels in diabetic women with fasting plasma insulin levels and plasma glucose levels obtained 1 h after oral administration of 50 g of glucose. Maternal serum leptin levels in women with gestational diabetes (mean +/- SD 16.52 +/- 5.07 ng/ml, range 10.84-27.4 ng/ml) were significantly higher (p < 0.001) than those found in uncomplicated pregnancies (10.61 +/- 1.47 ng/ml, range 7.28-13.4 ng/ml). A positive correlation was found between maternal serum leptin levels and glycosylated haemoglobin values in diabetic pregnant women (r = 0.94, p < 0.001). A positive correlation was also found between maternal leptin concentrations and fasting serum insulin levels, as well as between leptin concentrations and plasma glucose levels obtained 1 h after the administration of 50 g of glucose in women with gestational diabetes (r = 0.84, p < 0.001, and r = 0.92, p < 0.001, respectively). We conclude that leptin levels are elevated in pregnant women with gestational diabetes, and its metabolism depends on insulin levels and the severity of diabetes.