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

Abstract

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. 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. 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). 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.