Regulation of muscle growth in neonates.
OBJECTIVE
This review reports recent findings on the multiple factors that regulate skeletal muscle growth in neonates.


RESULTS
Skeletal muscle is the fastest growing protein mass in neonates. The high rate of neonatal muscle growth is due to accelerated rates of protein synthesis accompanied by the rapid accumulation of muscle nuclei. Feeding profoundly stimulates muscle protein synthesis in neonates and the response decreases with age. The feeding-induced stimulation of muscle protein synthesis is modulated by enhanced sensitivity to the postprandial rise in insulin and amino acids. Insulin and amino acid signaling components have been identified that are involved in the feeding-induced stimulation of protein synthesis in neonatal muscle. The enhanced activation of these signaling components in skeletal muscle of the neonate contributes to the high rate of muscle protein synthesis and rapid gain in muscle protein mass in neonates.


CONCLUSIONS
Recent findings suggest that the immature muscle has a heightened capacity to activate signaling cascades that promote translation initiation in response to the postprandial rise in insulin and amino acids thereby enabling their efficient utilization for muscle growth. This capacity is further supported by enhanced satellite cell proliferation, but how these two processes are linked remains to be established.
Davis
Teresa A
TA
USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA. tdavis@bcm.tmc.edu
Fiorotto
Marta L
ML
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001786:Blood Glucose / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism; D004435:Eating / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn / Q000254:growth & development*; D007328:Insulin / Q000378:metabolism; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000254:growth & development* / Q000378:metabolism; D032496:Satellite Cells, Skeletal Muscle / Q000378:metabolism
D000596:Amino Acids; D001786:Blood Glucose; D007328:Insulin; D009124:Muscle Proteins