The response of infants of diabetic women to tolbutamide and leucine at birth, and to glucose and tolbutamide at 2 years of age

Twelve newborn infants, 2 to 8 days old, of gestational (IGDM) and insulin-requiring (IDM) diabetic mothers responded to intravenous tolbutamide (20 mg/kg) with abnormally large decreases in plasma glucose and marked rises in plasma insulin (the latter was measured only in IGDM). Only 3 of 13 IGDM tested with leucine had significant decreases in plasma glucose. Newborn infants of normal mothers showed no changes in glucose or insulin in response to intravenous tolbutamide, and one of five had a small decrease in glucose levels after leucine. The results suggest the presence of large stores of pancreatic insulin in newborn infants of diabetic mothers which are more readily released by stimulation with tolbutamide than with leucine. The offspring of the diabetic women were restudied at 2 years of age for their response to intravenous tolbutamide and oral glucose. Seven of nine children had normal glucose and insulin levels after intravenous tolbutamide, and two had abnormally low glucose levels with high insulin levels. Three of the nine had normal glucose tolerance with normal insulin levels. The other six had abnormally elevated glucose levels which varied in duration from one-half to 2 hours. Four of the six had an accompanying hyperinsulinemia; two, who had diabetic glucose tolerance, had poor insulin responses. The findings in the 2-year-old children support a concept that the fetal environment provided by a diabetic woman has effects on carbohydrate tolerance which extend beyond the newborn period.