The underappreciated role of muscle in health and disease

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

Muscle plays a central role in whole-body protein metabolism by serving as the principal reservoir for amino acids to maintain protein synthesis in vital tissues and organs in the absence of amino acid absorption from the gut and by providing hepatic gluconeogenic precursors. Furthermore, altered muscle metabolism plays a key role in the genesis, and therefore the prevention, of many common pathologic conditions and chronic diseases. Nonetheless, the maintenance of adequate muscle mass, strength, and metabolic function has rarely, if ever, been targeted as a relevant endpoint of recommendations for dietary intake. It is therefore imperative that factors directly related to muscle mass, strength, and metabolic function be included in future studies designed to demonstrate optimal lifestyle behaviors throughout the life span, including physical activity and diet.

Related collections

Most cited references 52

Record: found
Abstract: found
Article: not found

Pathogenesis of NIDDM. A balanced overview.

R DeFronzo, R C Bonadonna, E Ferrannini (1992)

Non-insulin-dependent diabetes mellitus (NIDDM) results from an imbalance between insulin sensitivity and insulin secretion. Both longitudinal and cross-sectional studies have demonstrated that the earliest detectable abnormality in NIDDM is an impairment in the body's ability to respond to insulin. Because the pancreas is able to appropriately augment its secretion of insulin to offset the insulin resistance, glucose tolerance remains normal. With time, however, the beta-cell fails to maintain its high rate of insulin secretion and the relative insulinopenia (i.e., relative to the degree of insulin resistance) leads to the development of impaired glucose tolerance and eventually overt diabetes mellitus. The cause of pancreatic "exhaustion" remains unknown but may be related to the effect of glucose toxicity in a genetically predisposed beta-cell. Information concerning the loss of first-phase insulin secretion, altered pulsatility of insulin release, and enhanced proinsulin-insulin secretory ratio is discussed as it pertains to altered beta-cell function in NIDDM. Insulin resistance in NIDDM involves both hepatic and peripheral, muscle, tissues. In the postabsorptive state hepatic glucose output is normal or increased, despite the presence of fasting hyperinsulinemia, whereas the efficiency of tissue glucose uptake is reduced. In response to both endogenously secreted or exogenously administered insulin, hepatic glucose production fails to suppress normally and muscle glucose uptake is diminished. The accelerated rate of hepatic glucose output is due entirely to augmented gluconeogenesis. In muscle many cellular defects in insulin action have been described including impaired insulin-receptor tyrosine kinase activity, diminished glucose transport, and reduced glycogen synthase and pyruvate dehydrogenase. The abnormalities account for disturbances in the two major intracellular pathways of glucose disposal, glycogen synthesis, and glucose oxidation. In the earliest stages of NIDDM, the major defect involves the inability of insulin to promote glucose uptake and storage as glycogen. Other potential mechanisms that have been put forward to explain the insulin resistance, include increased lipid oxidation, altered skeletal muscle capillary density/fiber type/blood flow, impaired insulin transport across the vascular endothelium, increased amylin, calcitonin gene-related peptide levels, and glucose toxicity.

0 comments Cited 223 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Skeletal muscle fatty acid metabolism in association with insulin resistance, obesity, and weight loss.

D Kelley, B Goodpaster, R. R. Wing … (1999)

The current study was undertaken to investigate fatty acid metabolism by skeletal muscle to examine potential mechanisms that could lead to increased muscle triglyceride in obesity. Sixteen lean and 40 obese research volunteers had leg balance measurement of glucose and free fatty acid (FFA) uptake (fractional extraction of [9,10 (3)H]oleate) and indirect calorimetry across the leg to determine substrate oxidation during fasting and insulin-stimulated conditions. Muscle obtained by percutaneous biopsy had lower carnitine palmitoyl transferase (CPT) activity and oxidative enzyme activity in obesity (P < 0.05). During fasting conditions, obese subjects had an elevated leg respiratory quotient (RQ, 0.83 +/- 0.02 vs. 0.90 +/- 0.01; P < 0.01) and reduced fat oxidation but similar FFA uptake across the leg. During insulin infusions, fat oxidation by leg tissues was suppressed in lean but not obese subjects; rates of FFA uptake were similar. Fasting values for leg RQ correlated with insulin sensitivity (r = -0.57, P < 0.001). Thirty-two of the obese subjects were restudied after weight loss (WL, -14.0 +/- 0.9 kg); insulin sensitivity and insulin suppression of fat oxidation improved (P < 0.01), but fasting leg RQ (0.90 +/- 0.02 vs. 0.90 +/- 0.02, pre-WL vs. post-WL) and muscle CPT activity did not change. The findings suggest that triglyceride accumulation in skeletal muscle in obesity derives from reduced capacity for fat oxidation and that inflexibility in regulating fat oxidation, more than fatty acid uptake, is related to insulin resistance.

0 comments Cited 204 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: not found
Article: not found

Skeletal Muscle Strength as a Predictor of All-Cause Mortality in Healthy Men

E Metter, L A Talbot, Sheree Schrager … (2002)

0 comments Cited 177 times – based on 0 reviews      Review now

Bookmark

All references

Author and article information

Journal

Title: The American Journal of Clinical Nutrition

Publisher: Oxford University Press (OUP)

ISSN (Print): 0002-9165

ISSN (Electronic): 1938-3207

Publication date Created: December 2006

Publication date Created: December 01 2006

Publication date Other: December 2006

Publication date (Print): December 01 2006

Volume: 84

Issue: 3

Pages: 475-482

Affiliations

[1 ]From the University of Texas Medical Branch, Department of Surgery and Shriners Burns Hospital, Metabolism Unit, Galveston, TX

Article

DOI: 10.1093/ajcn/84.3.475

PubMed ID: 16960159

SO-VID: 2df42bbc-3d02-4ec3-8182-9ebe5fa9c518

History

Data availability:

Comments

Comment on this article

scite_

Smart Citations

Citing PublicationsSupportingMentioningContrasting

View Citations

See how this article has been cited at scite.ai

scite shows how a scientific paper has been cited by providing the context of the citation, a classification describing whether it supports, mentions, or contrasts the cited claim, and a label indicating in which section the citation was made.

The underappreciated role of muscle in health and disease

Read this article at

Abstract

Related collections

Alternative approaches to Alzheimer's Disease

Most cited references 52

Pathogenesis of NIDDM. A balanced overview.

Skeletal muscle fatty acid metabolism in association with insulin resistance, obesity, and weight loss.

Skeletal Muscle Strength as a Predictor of All-Cause Mortality in Healthy Men

Author and article information

Journal

Affiliations

Article

History

Comments

Comment on this article

Similar content 3,784

Cited by 439

Most referenced authors 810