BACKGROUND: Peptide YY (PYY) and ghrelin are gastrointestinal tract-derived hormones that play roles in the regulation of food intake and energy balance. Negative energy balance often occurs in hospitalized preterm infants. METHODS: To measure serum concentrations of PYY in preterm and full-term infants and to investigate their correlations with anthropometric characteristics, food intake, and serum ghrelin concentrations, we measured serum PYY and ghrelin concentrations by RIA in 62 healthy preterm infants [mean (SD) gestational age, 32.0 (2.1) weeks; postnatal age, 40.9 (14.8) days] and 15 healthy full-term infants of comparable postnatal age. All of the infants were formula-fed every 3 h. RESULTS: PYY concentrations were significantly higher in preterm [1126.2 (215.4) ng/L] than in full-term infants [825.3 (234.4) ng/L; P < 0.001]. In the entire study population, serum PYY concentrations correlated negatively with gestational age and anthropometric measurements (birth weight, body weight, body length, body mass index, and head circumference) and positively with serum ghrelin concentrations, whereas there was no significant correlation between PYY concentration and caloric intake or weight gain. Multiple regression analysis, after correction for prematurity, revealed that serum PYY concentrations correlated independently with serum ghrelin concentrations and infant body weight or body mass index. CONCLUSIONS: Circulating concentrations of PYY may increase in preterm infants to compensate for the negative body-weight balance. The physiologic mechanisms behind the correlation between PYY and ghrelin remain to be elucidated.

UNLABELLED: Abnormal glucose tolerance is a frequent late complication of cystic fibrosis (CF), but the prevalence of CF-related diabetes mellitus (CFRD) in children less than 10 y old is less than 2%. The youngest child with CFRD reported to date was 6 mo of age. Insulinopenia is the primary cause of abnormal glucose tolerance/CFRD, but it is unknown whether it may begin in the neonatal period. We describe a case of a neonate with CF who presented with hyperglycaemia in the diabetic range and marked insulinopenia. Insulinopenia and impaired glucose tolerance were permanent findings at 6 and 15 mo of age. CONCLUSION: This case suggests that abnormal glucose tolerance/diabetes may occur much earlier in the course of CF, even during neonatal age. Careful follow-up and further studies in CF infants could reveal that the real incidence of glucose intolerance and diabetes in this age group has been underestimated.