Lack of gastrointestinal enhancement of the insulin response to glucose in newborn infants.

Forty-five normal newborn infants were infused with glucose at constant rates by intravenous or nasogastric routes. Blood glucose rose to higher levels during IV than during NG infusions at identical rates; however, the glycemic responses were similar when NG glucose infusions at 12 mg/minute/kg were compared with IV infusions at 6 mg/minute/kg. The plasma insulin responses to glucose were not enhanced by NG administration. Thus, enterohormonal responses to glucose may not affect pancreatic beta cell regulation of glucose assimilation in the newborn period.