Ghrelin secretion in childhood is refractory to the inhibitory effect of feeding.
Ghrelin, a natural GH secretagogue, is predominantly produced by the stomach. Ghrelin has other actions including orexant activity, modulation of energy balance, and modulation of endocrine and nonendocrine functions. Ghrelin secretion is increased by fasting and energy restriction but decreased by food intake, glucose, insulin, and somatostatin. Ghrelin secretion does not seem to be a function of age; in fact, morning ghrelin levels after overnight fasting in prepubertal and pubertal children are similar to those in young adults. To clarify whether children and adults have the same sensitivity to the inhibitory effect of food intake, we studied the ghrelin response to a standardized light breakfast (SLB) in 10 prepubertal lean children whose results were compared with those recorded in 19 normal-weight adults. Basal ghrelin levels in children (median, 224.5; 25th to 75th percentile, 122.0-447.7 pg/ml) and adults (338.0; 238.0-512.0 pg/ml) were similar. SLB inhibited ghrelin levels in adults (263.0; 190.0-399.0 pg/ml). However, no change in ghrelin levels after SLB (206.5; 105.0-274.0 pg/ml) was recorded in children. Thus, food intake inhibits ghrelin secretion in adults but not in children. Ghrelin refractoriness to inhibition by food intake in children would reflect a peculiar functional profile of the ghrelin system in childhood.
Bellone
Simonetta
S
Units of Pediatrics, Department of Medical Sciences, University of Piemonte Orientale, 28100 Novara, Italy.
Castellino
Nadia
N
Broglio
Fabio
F
Rapa
Anna
A
Vivenza
Daniela
D
Radetti
Giorgio
G
Bellone
Jaele
J
Gottero
Cristina
C
Ghigo
Ezio
E
Bona
Gianni
G
D000328:Adult; D000375:Aging / Q000097:blood / Q000502:physiology; D002648:Child; D004435:Eating / Q000502:physiology*; D005260:Female; D054439:Ghrelin; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D036361:Peptide Hormones / Q000097:blood / Q000378:metabolism*; D019518:Postprandial Period
D054439:Ghrelin; D007328:Insulin; D036361:Peptide Hormones