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Review
. 2009 Jan;12(1):78-85.
doi: 10.1097/MCO.0b013e32831cef9f.

Regulation of muscle growth in neonates

Teresa A Davis  1 , Marta L Fiorotto
Affiliations
Review

Regulation of muscle growth in neonates

Teresa A Davis et al. Curr Opin Clin Nutr Metab Care. 2009 Jan.

Abstract

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

Recent findings: 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.

Summary: 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.

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Figures

Figure 1
Figure 1. Muscle protein accretion in early postnatal life
(a) Relative changes in the proportion of whole-body protein mass attributable to skeletal muscle protein in the rat between birth and weaning (Fiorotto et al., unpublished observations). (b) Relationship between the postnatal change in the rate of muscle protein accretion and the fractional rates of protein synthesis and degradation in skeletal muscle proteins during the suckling period in the hind limb muscles of rats [2,3]. formula image, Fractional synthesis rate; formula image, fractional accretion rate; formula image, fractional degradation rate.
Figure 2
Figure 2. Insulin and amino acid signaling pathways that lead to translation initiation
4EBP1, 4E-binding protein 1; AMPK, AMP-activated protein kinase; mTOR, mammalian target of rapamycin; PDK1, phosphoinositide-dependent kinase 1; PI3-K, phosphatidylinositol 3-kinase; PKB, protein kinase B; PP2A, protein phosphatase 2A; PTEN, phosphatase and tensin homologue deleted on chromosome 10; PTP1B, protein tyrosine phosphatase 1B; TSC, tuberous sclerosis complex.
Figure 3
Figure 3. Regulation of translation initiation
4EBP1, 4E-binding protein 1; GDP, guanosine diphosphate; GTP, guanosine triphosphate.
Figure 4
Figure 4. The relative consequence of suboptimal nutrition during the suckling period on total protein content and the ratio of protein to DNA in various hind limb muscles of weanling rats
Data were compiled from three studies: (a) [81], (b) [82], (c) [3]. EDL, extensor digitorum longus; Gastroc, gastrocnemius muscle; SOL, soleus. ■, Total protein; ▨, protein : DNA.
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References

    1. Fiorotto ML, Davis TA. Food intake alters muscle protein gain with little effect on Na(+)-K(+)-ATPase and myosin isoforms in suckled rats. Am J Physiol. 1997;272:R1461–R1471. - PubMed
    1. Davis TA, Fiorotto ML, Nguyen HV, Reeds PJ. Protein turnover in skeletal muscle of suckling rats. Am J Physiol. 1989;257:R1141–R1146. - PubMed
    1. Fiorotto ML, Davis TA, Reeds PJ. Regulation of myofibrillar protein turnover during maturation in normal and undernourished rat pups. Am J Physiol. 2000;278:845–854. - PubMed
    1. Davis TA, Fiorotto ML, Beckett PR, et al. Differential effects of insulin on peripheral and visceral tissue protein synthesis in neonatal pigs. Am J Physiol Endocrinol Metab. 2001;280:E770–E779. - PubMed
    1. Davis TA, Burrin DG, Fiorotto ML, Nguyen HV. Protein synthesis in skeletal muscle and jejunum is more responsive to feeding in 7- than 26-day-old pigs. Am J Physiol. 1996;270:E802–E809. - PubMed

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