Effect of starvation on human muscle protein metabolism and its response to insulin

Fryburg, David A.; Barrett, Eugene J.; Louard, Rita J.; Gelfand, R. A.

doi:10.1152/ajpendo.1990.259.4.e477

Cited by 57 publications

(51 citation statements)

References 9 publications

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“…Although nitrogen balance is negative in both cases (Svanfeldt et al, 2006), protein breakdown in starvation alone remains at near-normal values, whereas protein synthesis decreases (James, 1981;Arnal et al, 1987;Waterlow, 1995;Volpi et al, 1998) or, according to other reports, protein breakdown increases and protein synthesis remains unchanged (Frexes-Steed et al, 1990;Fryburg et al, 1990;Waterlow, 1995). A possible explanation for the differing response to fasting that occurs in injured vs healthy individuals is the different metabolic needs of the two situations.…”

Section: Discussionmentioning

confidence: 98%

Nutritional modulation of protein metabolism after gastrointestinal surgery

et al. 2007

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Background: The metabolic response to surgery includes alterations in protein metabolism, resulting in a net loss of proteins. Protein hypercatabolism is considered an unavoidable consequence of injury, and an important source of morbidity and mortality. Our purpose was to determine the effect of nutrition on protein metabolism following gastrointestinal surgery, and to elucidate whether postoperative protein loss can be prevented with adequate nutritional support. Methods: Patients who had undergone gastrointestinal surgery were given four different parenteral nutritions with increasing glucose, lipid and amino acid content during the 7 days following surgery. Nitrogen balance, protein synthesis and protein breakdown were determined using in vivo stable isotope labelling. Other metabolites (3-methylhistidine, creatinine, urea, cortisol, glucose, insulin, amino acids and C-reactive protein) were measured. Results: A nutrition-dependent alteration of protein metabolism was found in response to surgical injury. Nutrition modified nitrogen balance, whole-body protein breakdown and, to a lesser extent, whole-body protein synthesis and muscle protein breakdown. The low-energy parenteral nutrition without amino acids produced a negative nitrogen balance (postoperative day 7 ¼ À0.381 g protein kg À1 day À1 ) and important alterations in postoperative protein metabolism that did not normalize during the study period (day 7 protein synthesis ¼ 239% and protein breakdown 217% vs preoperative). Patients receiving the two low energy parenteral nutritions containing amino acids had a less negative nitrogen balance (day 7 ¼ À0.011 and À0.133 g protein kg À1 day À1 ) and a transient increase in protein metabolism. The complete parenteral nutrition maintained, during all studied days, protein metabolism parameters within the preoperative reference range (synthesis day 2 ¼ 92%, day 4 ¼ 110% day 7 ¼ 79%; breakdown day 2 ¼ 85%, day 4 ¼ 80%, day 7 ¼ 76% vs preoperative) and a positive nitrogen balance (day 2 ¼ þ 0.0387, day 4 ¼ þ 0.578 and day 7 ¼ þ 0.227 g protein kg À1 day À1 ). Conclusion: Complete nutritional support can prevent protein loss after gastrointestinal surgery and maintain protein metabolism without alterations.

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Section: Discussionmentioning

confidence: 98%

Nutritional modulation of protein metabolism after gastrointestinal surgery

et al. 2007

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“…18 As in our study, a sustained insulin secretion with CR has also been found by other studies to prevent unfavorable protein catabolism. 43 Effect of 1-week OF Fasting and postprandial IS were significantly impaired after 1-week OF ( þ 60% energy). Concomitantly, postprandial insulin secretion increased.…”

Section: Discussionmentioning

confidence: 99%

Effects of brief perturbations in energy balance on indices of glucose homeostasis in healthy lean men

et al. 2011

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BACKGROUND:Little is known about the effects of short-term caloric restriction (CR) and overfeeding (OF) on glucose homeostasis in healthy lean individuals. In addition, it remains unclear whether the effects of CR and OF are reversed by a complementary feeding period. METHODS: Ten healthy men participated in two cycles of controlled 7-day periods of CR and refeeding (RF; protocol A), and OF and CR (protocol B) at ±60% energy requirement. At baseline, insulin sensitivity (IS) was assessed by euglycemic clamp (M). Before and during each feeding cycle, fasting and oral glucose tolerance test-derived indices were used to estimate glucose tolerance, IS and glucose-stimulated insulin secretion. RESULTS: Clamp tests revealed normal IS at baseline (M-values 9.4 ± 2.1 mg kg À1 min À1 , coefficient of variation (CV) inter 22%). M-values were significantly correlated with indices of IS. In protocol A, CR-induced weight loss (À3.0±0.4 kg) was associated with an increase in fasting IS. Postprandial IS and glucose-stimulated insulin secretion remained unchanged, but glucose tolerance decreased. RF decreased fasting and postprandial IS at increased glucose-stimulated insulin secretion. In protocol B, OF significantly increased the body weight ( þ 1.6±0.9 kg). Concomitantly, fasting and postprandial IS decreased at increased glucose-stimulated insulin secretion. Subsequent CR reversed these effects. Inter-individual variability in indices of glucose metabolism was high with coefficients of variation ranging from 9 to 59%. CONCLUSION: Significant changes in glucose metabolism are evident within 7-day periods of controlled OF and underfeeding. Although IS was impaired at the end of the CR --RF cycle, IS was normalized after the OF --CR cycle. At different feeding regimens, homeostatic responses of glucose metabolism were highly variable. Keywords: insulin secretion; insulin sensitivity; glucose homeostasis; weight gain; energy balance INTRODUCTION Long-term perturbations in energy balance, either by overfeeding (OF) or underfeeding, are known to modulate insulin sensitivity (IS). Chronic OF and obesity are commonly characterized by insulin resistance, 1 which has been shown to be completely 2 or partially reversed by acute caloric restriction (CR), as well as by moderate weight loss. 3 --5 On the other hand, IS is preserved or even improved with chronic CR in patients with anorexia nervosa and returned to normal values at the end of refeeding (RF). 6 Although considerable research has been devoted to individuals outside the normal range of body weight, there are only few studies examining the effects of short-term controlled perturbations in energy balance on IS in lean subjects without confounding metabolic abnormalities. 7 --17 Moreover, these studies provide discordant findings that may depend on duration and degree of energy imbalance and macronutrient composition of the diets. Fasting (1 --3 days) consistently caused a decline in IS assessed by clamp-and intravenous glucose tolerance test. 7,8,17 Studies with less severe ...

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“…Leucine and phenylalanine specific activity were determined as previously described (18,19). Data analysis.…”

Section: Methodsmentioning

confidence: 99%

Insulin sensitivity of protein and glucose metabolism in human forearm skeletal muscle.

Louard¹,

Fryburg²,

Gelfand³

et al. 1992

J. Clin. Invest.

157

109

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IntroductionPhysiologic increases of insulin promote net amino acid uptake and protein anabolism in forearm skeletal muscle by restraining protein degradation. The sensitivity of this process to insulin is not known. Using the forearm perfusion method, we infused insulin locally in the brachial artery at rates of 0.00 (saline control), 0.01, 0.02, 0.035, or 0.05 mU/min per kg for 150 min to increase local forearm plasma insulin concentration by 0, -20, -35, -60, and -120 ,U/ml (n = 35). L-Iring-2,6-3Hjphenylalanine and L-11-14Cjleucine were infused systemically, and the net forearm balance, rate of appearance (R.) and rate of disposal (Rd) of phenylalanine and leucine, and forearm glucose balance were measured basally and in response to insulin infusion. Compared to saline, increasing rates of insulin infusion progressively increased net forearm glucose uptake from 0.9 Mmol/min per 100 ml (saline) to 1.0, 1.8, 2.4, and 4.7 ,umol/min per 100 ml forearm, respectively. Net forearm balance for phenylalanine and leucine was significantly less negative than basal (P < 0.01 for each) in response to the lowest dose insulin infusion, 0.01 mU/min per kg, and all higher rates of insulin infusion. The effects ofhyperinsulinemia on skeletal muscle, the largest pool of protein in the body, has been of particular interest. Pozefsky et al. (9), using the forearm perfusion technique, observed that local hyperinsulinemia diminished net forearm amino acid release and stimulated glucose uptake. With direct infusion of insulin into the brachial artery, the effects of hyperinsulinemia on forearm skeletal muscle metabolism can be examined directly (9-13) without the confounding influence of altered substrate concentrations that accompany systemic insulin administration (14,15

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Effect of starvation on human muscle protein metabolism and its response to insulin

Cited by 57 publications

References 9 publications

Nutritional modulation of protein metabolism after gastrointestinal surgery

Nutritional modulation of protein metabolism after gastrointestinal surgery

Effects of brief perturbations in energy balance on indices of glucose homeostasis in healthy lean men

Insulin sensitivity of protein and glucose metabolism in human forearm skeletal muscle.

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