HYPERINSULINISM IN INFANTS OF DIABETIC MOTHERS . SUPPRESSION BY SOMATOSTATIN INFUSION

Abstract

Post natal hypoglycemia is presently the major complication that occurs in infants of diabetic mothers (IDM) and this complication may be related to the hyperinsulinism state thought to be present in fetuses of diabetic women. Because of sudden and asymptomatic hypoglycemia, hypoglycemic risk persists in despite of present neonatal managment. We studied the somatostatin effect on transient hyperinsulinism of IDM in neonatal period. Five IDM were studied at this time. Synthetic cyclic somatostatin (provided by CLIN-MIDY Laboratories) was infused at the rate of 4 μg/kg/h, a glucose infusion (0.5 g/kg/h) was maintened throughout the study course. Plasma C Peptide (CPR) determined by radioimmunoassay (Mallinckrodt) may provide a mean of studying beta cell function in IDM because insulin antibodies cross the placenta. The cross reactivity with human proinsulin is about 10 %. Before somatostatin administration, plasma CPR was inapropriatly elevated for the blood glucose levels. Plasma CPR/glucose ratio was high. During somatostatin infusion plasma CPR dropped within the first hour and normal level was obtained before the fourth hour in three cases. Blood glucose was maintened over 5.5 mmol/1. Plasma CPR escaped from suppression just after somatostatin infusion although blood glucose moderatly rose. No side effect was observed. Our findings show that beta cells may be more sensitive than alpha cells to somatostatin suppression as previously suggested in nesidioblastosis. The parent gave informed consent and this study was approved by the ethical comittee.