Stimulation of protein synthesis by both insulin and amino acids is unique to skeletal muscle in neonatal pigs

Davis, Teresa A.; Fiorotto, Marta L.; Burrin, Douglas G.; Reeds, Peter J.; Nguyen, Hanh V.; Beckett, Philip R.; Vann, R. C.; O'Connor, Pamela M. J.

doi:10.1152/ajpendo.00517.2001

Cited by 167 publications

(237 citation statements)

References 61 publications

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“…This feeding-induced activation of the IR, IRS-I, PI 3-kinase, and protein kinase B decreases with development in parallel with the developmental decline in the feeding-induced activation of translation initiation factors that regulate the binding of mRNA to 43S ribosomal complex. These developmental changes also parallel the developmental changes in the ability of feeding and insulin infusion to stimulate protein synthesis and are specific to skeletal muscle (13,15). Because of the profound developmental decline in an initial step in the insulin-signaling cascade, i.e., the tyrosine phosphorylation of the IR (37), it was crucial that we ascertain the mechanism involved in this developmental decline in IR activation.…”

Section: Discussionmentioning

confidence: 95%

“…Furthermore, we also studied the mechanisms involved in PTP1B activation by measuring the association of PTP1B with the IR, the tyrosine phosphorylation of PTP1B, and the association of PTP1B with Grb2 adaptor protein. For comparison, similar measurements were also made in liver, an organ in which insulin does not stimulate protein synthesis (14,15) and which shows no developmental decline in insulin signaling (37).…”

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confidence: 99%

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Protein-tyrosine-phosphatase 1B activation is regulated developmentally in muscle of neonatal pigs

Suryawan

Davis

2003

American Journal of Physiology-Endocrinology and Metabolism

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Suryawan, Agus, and Teresa A. Davis. Protein-tyrosine-phosphatase 1B activation is regulated developmentally in muscle of neonatal pigs. Am J Physiol Endocrinol Metab 284: E47-E54, 2003. First published September 11, 2002 10.1152/ajpendo.00210.2002The high activity of the insulin-signaling pathway contributes to the enhanced feeding-induced stimulation of translation initiation in skeletal muscle of neonatal pigs. Protein-tyrosine-phosphatase 1B (PTP1B) is a negative regulator of the tyrosine phosphorylation of the insulin receptor (IR) and insulin receptor substrate 1 (IRS-1). The activity of PTP1B is determined mainly by its association with IR and Grb2. We examined the level of PTP1B activity, PTP1B protein abundance, PTP1B tyrosine phosphorylation, and the association of PTP1B with IR and Grb2 in skeletal muscle and liver of fasted and fed 7-and 26-day-old pigs. PTP1B activity in skeletal muscle was lower (P Ͻ 0.05) in 7-compared with 26-day-old pigs but in liver was similar in the two age groups. PTP1B abundances were similar in muscle but lower (P Ͻ 0.05) in liver of 7-compared with 26-day-old pigs. PTP1B tyrosine phosphorylation in muscle was lower (P Ͻ 0.05) in 7-than in 26-day-old pigs. The associations of PTP1B with IR and with Grb2 were lower (P Ͻ 0.05) at 7 than at 26 days of age in muscle, but there were no age effects in liver. Finally, in both age groups, fasting did not have any effect on these parameters. These results indicate that basal PTP1B activation is developmentally regulated in skeletal muscle of neonatal pigs, consistent with the developmental changes in the activation of the insulin-signaling pathway reported previously. Reduced PTP1B activation in neonatal muscle likely contributes to the enhanced insulin sensitivity of skeletal muscle in neonatal pigs.neonate; insulin signaling; insulin sensitivity; protein synthesis THE ENHANCED ACTIVATION of the insulin-signaling pathway leading to translation initiation in skeletal muscle of the neonate after food consumption has an important role in the enhanced responsiveness of muscle protein synthesis to feeding in the neonate (13,16,26,27,37). We have shown that the feeding-induced activation of the insulin receptor (IR), insulin receptor substrate-1 (IRS-1), and phosphatidylinositol 3-kinase (PI 3-kinase), as well as the abundance of the IR, is enhanced in skeletal muscle of the neonatal pig and decreases markedly with development. This developmental decline in the feeding-induced activation of early insulin-signaling components parallels the developmental decline in the feeding-induced activation of downstream signaling proteins, leading to the stimulation of protein synthesis in skeletal muscle and the developmental decrease in the ability of insulin to stimulate muscle protein synthesis. However, the molecular mechanism that regulates the developmental decline in the insulin sensitivity of skeletal muscle in neonatal pigs has not been elucidated.When insulin binds to its receptor, it induces autophosphorylation of the receptor on its ty...

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Section: Discussionmentioning

confidence: 95%

mentioning

confidence: 99%

Protein-tyrosine-phosphatase 1B activation is regulated developmentally in muscle of neonatal pigs

Suryawan

Davis

2003

American Journal of Physiology-Endocrinology and Metabolism

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“…Similarly, Davis et al (2002) have observed a developmental decline in amino acid-induced stimulation of hepatic protein synthesis in the growing animal. From these studies, one might infer that there is a decreased sensitivity of the liver to amino acids during ageing.…”

Section: Towards a Portal Amino Acid Signal?mentioning

confidence: 85%

Regulation of hepatic metabolism by enteral delivery of nutrients

et al. 2006

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The liver plays a unique role in nutrient homeostasis. Its anatomical location makes it ideally suited to control the systemic supply of absorbed nutrients, and it is the primary organ that can both consume and produce substantial amounts of glucose. Moreover, it is the site of a substantial fraction (about 25 %) of the body's protein synthesis, and the liver and other organs of the splanchnic bed play an important role in sparing dietary N by storing ingested amino acids. This hepatic anabolism is under the control of hormonal and nutritional changes that occur during food intake. In particular, the route of nutrient delivery, i.e. oral (or intraportal) v. peripheral venous, appears to impact upon the disposition of the macronutrients and also to affect both hepatic and whole-body nutrient metabolism. Intraportal glucose delivery significantly enhances net hepatic glucose uptake, compared with glucose infusion via a peripheral vein. On the other hand, concomitant intraportal infusion of both glucose and gluconeogenic amino acids significantly decreases net hepatic glucose uptake, compared with infusion of the same mass of glucose by itself. Delivery of amino acids via the portal vein may enhance their hepatic uptake, however. Elevation of circulating lipids under postprandial conditions appears to impair both hepatic and whole-body glucose disposal. Thus, the liver's role in nutrient disposal and metabolism is highly responsive to the route of nutrient delivery, and this is an important consideration in planning nutrition support and optimising anabolism in vulnerable patients.

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“…Previously, our group has developed and successfully implemented a stable isotope method to measure the in vivo fractional synthesis and breakdown rates (FSR 2 and FBR, respectively) of skin protein (1)(2)(3). Using this and other methods, we and others have reported the unique features of skin and wound protein metabolism (1,2,4) and its responses to nutritional and hormonal interventions (3,5,6). Amino acid (AA) supplementations and insulin (INS) are of particular interest among these interventional factors due to their well known anabolic effect on muscle and importance in wound healing (7,8).…”

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confidence: 99%

“…The skin protein NB did not change in response to any treatment as compared with the control group (3). In 7-day-old neonatal pigs, both INS alone and INS ϩ AA increased the skin protein FSR, whereas in 26-day-old pigs only INS ϩ AA increased the skin protein FSR (5). The effect of AA and INS has been also studied in an animal model of skin wounds (9) and donor site wounds in burn patients (10).…”

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Amino Acid Availability Regulates the Effect of Hyperinsulinemia on Skin Protein Metabolism in Pigs

Tuvdendorj¹,

Børsheim²,

Sharp

et al. 2015

Journal of Biological Chemistry

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Background: Insulin is known as an anabolic agent; however, its effect on skin protein metabolism is not well understood. Results: Hyperaminoacidemia alters the effect of hyperinsulinemia on skin protein metabolism in pigs. Conclusion: Hyperinsulinemia itself was not anabolic but rather affected skin amino acid cycling. Significance: Knowing the effect of hyperinsulinemia on skin protein metabolism will help with understanding the pathophysiology of skin conditions.

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Stimulation of protein synthesis by both insulin and amino acids is unique to skeletal muscle in neonatal pigs

Cited by 167 publications

References 61 publications

Protein-tyrosine-phosphatase 1B activation is regulated developmentally in muscle of neonatal pigs

Protein-tyrosine-phosphatase 1B activation is regulated developmentally in muscle of neonatal pigs

Regulation of hepatic metabolism by enteral delivery of nutrients

Amino Acid Availability Regulates the Effect of Hyperinsulinemia on Skin Protein Metabolism in Pigs

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