Ghrelin, motilin, insulin concentration in healthy infants in the first months of life: relation to fasting time and anthropometry.

AIMS: This study aimed to investigate: (i) the relation between fasting time and serum ghrelin, motilin and insulin concentrations and (ii) the correlations between these hormones and anthropometrical parameters of infants in the first 18 months of life. PATIENT AND METHODS: A cross-sectional study on 62 term infants was performed. Blood samples for hormonal assay were obtained at least 1 h after feeding. Weight, length and head circumference were recorded. Plasma ghrelin, motilin and insulin concentrations were determined by radioimmunoassay. RESULTS: Ghrelin and motilin had a significant direct correlation with fasting time (r = 0.447; P < 0.001 and r = 0.36; P = 0.004, respectively). We observed a negative influence of insulin on ghrelin levels (beta = -0.32; P = 0.036). Plasma ghrelin levels correlated significantly with age (r = 0.45, P < 0.001), weight (r = 0.31, P = 0.013), head circumference (r = 0.35, P = 0.006) and length (r = 0.39, P = 0.001). A significant correlation emerged between motilin and age (r = 0.45, P < 0.001), weight (r = 0.43, P = 0.001), head circumference (r = 0.47, P < 0.001) and length (r = 0.48, P < 0.001). CONCLUSIONS: Fasting influence on serum ghrelin concentration confirms the role of this hormone as a physiological meal initiator also in infancy. The correlation between ghrelin, anthropometrical parameters and age supports the hypothesis that this hormone could exert an important influence on growth in the first months of life. Considering motilin, age and weight might play a role in determining its secretion; motilin could be considered one of the numerous factors involved in long-term regulation of energy balance.

Serum ghrelin concentration and weight gain in healthy term infants in the first year of life.

OBJECTIVES: Ghrelin, a recently discovered hormone mainly secreted by the stomach, has several metabolic functions including regulation of food intake, energy homeostasis and body weight. There are few studies on this hormone in healthy infants during the first year of life. The aim of this study was to examine the correlations between ghrelin and weight gain in healthy term infants in the first year of life. METHODS: 104 healthy term infants aged 0 to 12 months were included in a cross-sectional study. Anthropometric measurements were assessed and mean weight gain was calculated. Serum ghrelin concentrations have been determined at least 3 hours after feeding by radioimmunoassay test. RESULTS: Ghrelin concentrations were correlated negatively to weight gain (r=-0.302; P=0.003) and positively to age (r = 0.412; P < 0.001), weight (r = 0.374; P < 0.001) and length (r=0.387; P<0.001). In breastfed infants a statistically significant negative correlation between ghrelin concentration and infant weight gain (r=-0.407; P=0.001) was observed, whereas in formula-fed infants this correlation was not statistically significant (r=-0.067; P=0.719). CONCLUSIONS: The negative correlation observed between ghrelin concentration and infant weight gain suggests that ghrelin might also play a role in the regulation of body weight in healthy infants with a physiologic energy balance. Further studies are needed to clarify how ghrelin might be involved in both short-term and long-term energy balance.