SUMMARY The hormonal and metabolic response to the first feed of breast milk was studied in 12 infants at 4-6 hours of age. After the feed there was an increase in blood glucose concentration but no changes in the concentrations of lactate, pyruvate, alanine, or ketone bodies. The feed was followed by an increase in the concentrations of plasma insulin, growth hormone, gastrin, and enteroglucagon, but no change in levels of plasma glucagon or gastric inhibitory peptide. Several hormone systems are functionally active at birth and are stimulated by the first feed of milk.At birth the continuous supply of nutrients which the fetus received across the placenta is interrupted and the neonate has to adapt to a new environment of intermittent feeding and fasting. There is evidence that changes in plasma hormone concentrations after birth are responsible for some of the changes in hepatic enzyme activity which occur during the period of metabolic adaptation (Shelley et al., 1975). Animal studies have shown that postnatal feeding modulates the development of glucose-stimulated insulin secretion (Gentz et al., 1971;Asplund, 1972). However, the effect of feeding on gastrointestinal and pancreatic insular hormone secretion and their relationship to circulating blood metabolite concentrations have not been studied in the human newborn.We report measurements of the blood levels of several hormones and metabolites before and after the first feed of expressed breast milk in a group of infants suffering from moderately severe respiratory distress.
Patients and methodsTwelve infants were studied with the approval of the Ethical Committee. All had been admitted to the special care baby unit, and all had indwelling umbilical arterial catheters for clinical monitoring purposes. They were nursed in infant incubators at an environmental temperature appropriate for their weight and gestation (Hey and Katz, 1970). None had a rectal temperature lower than 360C at the time Received 27 July 1976 of the study. The mean birthweight was 2945 g (range 2110-3940 g) and mean gestational age 37 8 weeks (range 37-39 weeks). 9 infants were suffering from moderately severe respiratory distress requiring enriched inspired oxygen concentrations. Of the other 3, one was a breech delivery with severe birth asphyxia and 2 had lesser degrees of birth asphyxia requiring transient endotracheal intubation, oxygen, and alkali therapy. None had an arterial pH <7 25, and the inspired oxygen concentration was adjusted to maintain the Pao2 in the range 60-90 torr. No change in inspired oxygen concentration was required during the study period and the clinical condition of the infants did not change.Feeding procedure. The first feed was given between 4 and 6 hours of age. Nasogastric tubes were inserted and the stomach contents aspirated 30 minutes before the feed. When the contents were copious, tenacious, or heavily stained with meconium 5-10 ml of 0 9% saline at 37°C were used to irrigate the stomach, the contents being reaspirated. The infants were then gi...