Effects of ingesting protein with various forms of carbohydrate following resistance exercise on substrate availability and markers of catabolism.
Lundberg <found this one on microfice, sorry, I'm not typing it out, but if you are serious about the subject, you'll want to look it up>
Dietary supplements affect the anabolic hormones after weight-training exercise.
Chandler RM, Byrne HK, Patterson JG, Ivy JL
J Appl Physiol 1994 Feb 76:839-45
J Appl Physiol • Volume 76 • Issue 2
Abstract
To examine the effect of carbohydrate and/or protein supplements on the hormonal state of the body after weight-training exercise, nine experienced male weight lifters were given water (Control) or an isocaloric carbohydrate (CHO; 1.5 g/kg body wt), protein (PRO; 1.38 g/kg body wt), or carbohydrate-protein (CHO/PRO; 1.06 g carbohydrate/kg body wt and 0.41 g protein/kg) supplement immediately and 2 h after a standardized weight-training workout. Venous blood samples were drawn before and immediately after exercise and during 8 h of recovery. Exercise induced elevations in lactate, glucose, testosterone, and growth hormone. CHO and CHO/PRO stimulated higher insulin concentrations than PRO and Control. CHO/PRO led to an increase in growth hormone 6 h postexercise that was greater than PRO and Control. Supplements had no effect on insulin-like growth factor I but caused a significant decline in testosterone. The decline in testosterone, however, was not associated with a decline in luteinizing hormone, suggesting an increased clearance of testosterone after supplementation. The results suggest that nutritive supplements after weight-training exercise can produce a hormonal environment during recovery that may be favorable to muscle growth by stimulating insulin and growth hormone elevations.
Carbohydrate ingestion/supplementation or resistance exercise and training.
Conley MS, Stone MH
Sports Med 1996 Jan 21:7-17
Sports Med • Volume 21 • Issue 1
Abstract
The physiological and performance effects of carbohydrate ingestion/supplementation on aerobic endurance exercise have been extensively studied. However, little attention has been given to the effects of carbohydrate ingestion on resistance exercise and training. Recent evidence suggests that resistance exercise can elicit a considerable glycogenolytic effect, which can lead to fatigue and strength loss. The ability of carbohydrate ingestion immediately before and during resistance exercise to enhance performance is unclear at present, however carbohydrate ingestion following resistance exercise has been shown to enhance muscle glycogen resynthesis. This may decrease recovery time following resistance exercise and enable an increase in training volume which may enhance physiological adaptations. Also, carbohydrate ingestion during or immediately after resistance exercise has been shown to increase postexercise insulin and growth hormone levels, which may lead to increased protein synthesis and hypertrophy, although this has not been systematically investigated.
Effect of glucose supplement timing on protein metabolism after resistance training
B. D. Roy1, M. A. Tarnopolsky1,2, J. D. Macdougall1, J. Fowles1, and K. E. Yarasheski3
1 Department of Kinesiology and 2 Department of Neurology and Physical Medicine and Rehabilitation, McMaster University, Hamilton, Ontario, Canada L8S 4K1; and 3 Metabolism Division, Washington University School of Medicine, St. Louis, Missouri 63110
Received 16 September 1996; accepted in final form 10 February 1997.
Roy, B. D., M. A. Tarnopolsky, J. D. MacDougall, J. Fowles, and K. E. Yarasheski. Effect of glucose supplement timing on protein metabolism after resistance training. J. Appl. Physiol. 82(6): 1882-1888, 1997.We determined the effect of the timing of glucose supplementation on fractional muscle protein synthetic rate (FSR), urinary urea excretion, and whole body and myofibrillar protein degradation after resistance exercise. Eight healthy men performed unilateral knee extensor exercise (8 sets/~10 repetitions/~85% of 1 single maximal repetition). They received a carbohydrate (CHO) supplement (1 g/kg) or placebo (Pl) immediately (t = 0 h) and 1 h (t = +1 h) postexercise. FSR was determined for exercised (Ex) and control (Con) limbs by incremental L-[1-13C]leucine enrichment into the vastus lateralis over ~10 h postexercise. Insulin was greater (P < 0.01) at 0.5, 0.75, 1.25, 1.5, 1.75, and 2 h, and glucose was greater (P < 0.05) at 0.5 and 0.75 h for CHO compared with Pl condition. FSR was 36.1% greater in the CHO/Ex leg than in the CHO/Con leg (P = not significant) and 6.3% greater in the Pl/Ex leg than in the Pl/Con leg (P = not significant). 3-Methylhistidine excretion was lower in the CHO (110.43 ± 3.62 µmol/g creatinine) than Pl condition (120.14 ± 5.82, P < 0.05) as was urinary urea nitrogen (8.60 ± 0.66 vs. 12.28 ± 1.84 g/g creatinine, P < 0.05). This suggests that CHO supplementation (1 g/kg) immediately and 1 h after resistance exercise can decrease myofibrillar protein breakdown and urinary urea excretion, resulting in a more positive body protein balance.
Ingestion of Protein Hydrolysate and Amino Acid-Carbohydrate Mixtures Increases Postexercise Plasma Insulin Responses in Men
Luc J. C. van Loon*2, Margriet Kruijshoop*, Hans Verhagen, Wim H. M. Saris* and Anton J. M. Wagenmakers*
* Nutrition and Toxicology Research Institute NUTRIM, Department of Human Biology, Maastricht University, 6200 MD Maastricht, the Netherlands and TNO Nutrition and Food Research Institute, Food and Non-Food Analysis Department, Zeist, the Netherlands
To optimize the postexercise insulin response and to increase plasma amino acid availability, we studied postexercise insulin levels after the ingestion of carbohydrate and wheat protein hydrolysate with and without free leucine and phenylalanine. After an overnight fast, eight male cyclists visited our laboratory on five occasions, during which a control drink and two different beverage compositions in two different doses were tested. After they performed a glycogen-depletion protocol, subjects received a beverage (3.5 mL · kg-1) every 30 min to ensure an intake of 1.2 g · kg-1 · h-1 carbohydrate and 0, 0.2 or 0.4 g · kg-1 · h-1 protein hydrolysate (and amino acid) mixture. After the insulin response was expressed as the area under the curve, only the ingestion of the beverages containing wheat protein hydrolysate, leucine and phenylalanine resulted in a marked increase in insulin response (+52 and + 107% for the 0.2 and 0.4 g · kg-1 · h-1 mixtures, respectively; P < 0.05) compared with the carbohydrate-only trial). A dose-related effect existed because doubling the dose (0.2–0.4 g · kg-1 · h-1) led to an additional rise in insulin response (P < 0.05). Plasma leucine, phenylalanine and tyrosine concentrations showed strong correlations with the insulin response (P < 0.0001). This study provides a practical tool to markedly elevate insulin levels and plasma amino acid availability through dietary manipulation, which may be of great value in clinical nutrition, (recovery) sports drinks and metabolic research. <BTW, my favorite post-exercise carb - maltodextrin - was used in this study.>
Muscle glycogen storage after prolonged exercise: effect of the glycemic index of carbohydrate feedings.
Burke LM, Collier GR, Hargreaves M
J Appl Physiol 1993 Aug 75:1019-23
J Appl Physiol • Volume 75 • Issue 2
Abstract
The effect of the glycemic index (GI) of postexercise carbohydrate intake on muscle glycogen storage was investigated. Five well-trained cyclists undertook an exercise trial to deplete muscle glycogen (2 h at 75% of maximal O2 uptake followed by four 30-s sprints) on two occasions, 1 wk apart. For 24 h after each trial, subjects rested and consumed a diet composed exclusively of high-carbohydrate foods, with one trial providing foods with a high GI (HI GI) and the other providing foods with a low GI (LO GI). Total carbohydrate intake over the 24 h was 10 g/kg of body mass, evenly distributed between meals eaten 0, 4, 8, and 21 h postexercise. Blood samples were drawn before exercise, immediately after exercise, immediately before each meal, and 30, 60, and 90 min post-prandially. Muscle biopsies were taken from the vastus lateralis immediately after exercise and after 24 h. When the effects of the immediate postexercise meal were excluded, the totals of the incremental glucose and insulin areas after each meal were greater (P < or = 0.05) for the HI GI meals than for the LO GI meals. The increase in muscle glycogen content after 24 h of recovery was greater (P = 0.02) with the HI GI diet (106 +/- 11.7 mmol/kg wet wt) than with the LO GI diet (71.5 +/- 6.5 mmol/kg). The results suggest that the most rapid increase in muscle glycogen content during the first 24 h of recovery is achieved by consuming foods with a high GI.
An oral essential amino acid-carbohydrate supplement enhances muscle protein anabolism after resistance exercise
Blake B. Rasmussen, Kevin D. Tipton, Sharon L. Miller, Steven E. Wolf, and Robert R. Wolfe
Department of Surgery, University of Texas Medical Branch and Metabolism Unit, Shriners Burns Institute, Galveston, Texas 77550
This study was designed to determine the response of muscle protein to the bolus ingestion of a drink containing essential amino acids and carbohydrate after resistance exercise. Six subjects (3 men, 3 women) randomly consumed a treatment drink (6 g essential amino acids, 35 g sucrose) or a flavored placebo drink 1 h or 3 h after a bout of resistance exercise on two separate occasions. We used a three-compartment model for determination of leg muscle protein kinetics. The model involves the infusion of ring-2H5-phenylalanine, femoral arterial and venous blood sampling, and muscle biopsies. Phenylalanine net balance and muscle protein synthesis were significantly increased above the predrink and corresponding placebo value (P < 0.05) when the drink was taken 1 or 3 h after exercise but not when the placebo was ingested at 1 or 3 h. The response to the amino acid-carbohydrate drink produced similar anabolic responses at 1 and 3 h. Muscle protein breakdown did not change in response to the drink. We conclude that essential amino acids with carbohydrates stimulate muscle protein anabolism by increasing muscle protein synthesis when ingested 1 or 3 h after resistance exercise.
Insulin action on muscle protein kinetics and amino acid transport during recovery after resistance exercise.
Biolo G, Williams BD, Fleming RY, Wolfe RR
Diabetes 1999 May 48:949-57
Diabetes • Volume 48 • Issue 5
Abstract
We have determined the individual and combined effects of insulin and prior exercise on leg muscle protein synthesis and degradation, amino acid transport, glucose uptake, and alanine metabolism. Normal volunteers were studied in the postabsorptive state at rest and about 3 h after a heavy leg resistance exercise routine. The leg arteriovenous balance technique was used in combination with stable isotopic tracers of amino acids and biopsies of the vastus lateralis muscle. Insulin was infused into a femoral artery to increase the leg insulin concentrations to high physiologic levels without substantively affecting the whole-body level. Protein synthesis and degradation were determined as rates of intramuscular phenylalanine utilization and appearance, and muscle fractional synthetic rate (FSR) was also determined. Leg blood flow was greater after exercise than at rest (P<0.05). Insulin accelerated blood flow at rest but not after exercise (P<0.05). The rates of protein synthesis and degradation were greater during the postexercise recovery (65+/-10 and 74+/-10 nmol x min(-1) x 100 ml(-1) leg volume, respectively) than at rest (30+/-7 and 46+/-8 nmol x min(-1) x 100 ml(-1) leg volume, respectively; P<0.05). Insulin infusion increased protein synthesis at rest (51+/-4 nmol x min(-1) x 100 ml(-1) leg volume) but not during the postexercise recovery (64+/-9 nmol x min(-1) x 100 ml(-1) leg volume; P<0.05). Insulin infusion at rest did not change the rate of protein degradation (48+/-3 nmol x min(-1) 100 ml(-1) leg volume). In contrast, insulin infusion after exercise significantly decreased the rate of protein degradation (52+/-9 nmol x min(-1) x 100 ml(-1) leg volume). The insulin stimulatory effects on inward alanine transport and glucose uptake were three times greater during the postexercise recovery than at rest (P<0.05). In contrast, the insulin effects on phenylalanine, leucine, and lysine transport were similar at rest and after exercise. In conclusion, the ability of insulin to stimulate glucose uptake and alanine transport and to suppress protein degradation in skeletal muscle is increased after resistance exercise. Decreased amino acid availability may limit the stimulatory effect of insulin on muscle protein synthesis after exercise.
Exercise Effects on Muscle Insulin Signaling and Action
Invited Review: Role of insulin in translational control of protein synthesis in skeletal muscle by amino acids or exercise
Scot R. Kimball1, Peter A. Farrell2, and Leonard S. Jefferson1
1 Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey 17033; and 2 Noll Physiology Research Center, The Pennsylvania State University, University Park, Pennsylvania 16802
Protein synthesis in skeletal muscle is modulated in response to a variety of stimuli. Two stimuli receiving a great deal of recent attention are increased amino acid availability and exercise. Both of these effectors stimulate protein synthesis in part through activation of translation initiation. However, the full response of translation initiation and protein synthesis to either effector is not observed in the absence of a minimal concentration of insulin. The combination of insulin and either increased amino acid availability or endurance exercise stimulates translation initiation and protein synthesis in part through activation of the ribosomal protein S6 protein kinase S6K1 as well as through enhanced association of eukaryotic initiation factor eIF4G with eIF4E, an event that promotes binding of mRNA to the ribosome. In contrast, insulin in combination with resistance exercise stimulates translation initiation and protein synthesis through enhanced activity of a guanine nucleotide exchange protein referred to as eIF2B. In both cases, the amount of insulin required for the effects is low, and a concentration of the hormone that approximates that observed in fasting animals is sufficient for maximal stimulation. This review summarizes the results of a number of recent studies that have helped to establish our present understanding of the interactions of insulin, amino acids, and exercise in the regulation of protein synthesis in skeletal muscle.
Dietary supplements and the promotion of muscle growth with resistance exercise.
Kreider RB
Sports Med 1999 Feb 27:97-110
Sports Med • Volume 27 • Issue 2
Abstract
Nutritional strategies of overfeeding, ingesting carbohydrate/protein before and after exercise, and dietary supplementation of various nutrients [e.g. protein, glutamine, branched-chain amino acid, creatine, leucine, beta-hydroxy beta-methyl-butyrate (beta-HMB), chromium, vanadyl sulfate, boron, prasterone (dehydroepiandrosterone [DHEA]) and androstenedione] have been purported to promote gains in fat-free mass during resistance training. Most studies indicate that chromium, vanadyl sulfate and boron supplementation do not affect muscle growth. However, there is evidence that ingesting carbohydrate/protein prior to exercise may reduce catabolism during exercise and that ingesting carbohydrate/protein following resistance-exercise may promote a more anabolic hormonal profile. Furthermore, glutamine, creatine, leucine, and calcium beta-HMB may affect protein synthesis. Creatine and calcium beta-HMB supplementation during resistance training have been reported to increase fat-free mass in athletic and nonathletic populations. Prasterone supplementation has been reported to increase testosterone and fat-free mass in nontrained populations. However, results are equivocal, studies have yet to be conducted on athletes, and prasterone is considered a banned substance by some athletic organisations. This paper discusses rationale and effectiveness of these nutritional strategies in promoting lean tissue accretion during resistance training.
Muscle glycogen synthesis before and after exercise.
Ivy JL
Sports Med 1991 Jan 11:6-19
Sports Med • Volume 11 • Issue 1
Abstract
The importance of carbohydrates as a fuel source during endurance exercise has been known for 60 years. With the advent of the muscle biopsy needle in the 1960s, it was determined that the major source of carbohydrate during exercise was the muscle glycogen stores. It was demonstrated that the capacity to exercise at intensities between 65 to 75% VO2max was related to the pre-exercise level of muscle glycogen, i.e. the greater the muscle glycogen stores, the longer the exercise time to exhaustion. Because of the paramount importance of muscle glycogen during prolonged, intense exercise, a considerable amount of research has been conducted in an attempt to design the best regimen to elevate the muscle's glycogen stores prior to competition and to determine the most effective means of rapidly replenishing the muscle glycogen stores after exercise. The rate-limiting step in glycogen synthesis is the transfer of glucose from uridine diphosphate-glucose to an amylose chain. This reaction is catalysed by the enzyme glycogen synthase which can exist in a glucose-6-phosphate-dependent, inactive form (D-form) and a glucose-6-phosphate-independent, active form (I-form). The conversion of glycogen synthase from one form to the other is controlled by phosphorylation-dephosphorylation reactions. The muscle glycogen concentration can vary greatly depending on training status, exercise routines and diet. The pattern of muscle glycogen resynthesis following exercise-induced depletion is biphasic. Following the cessation of exercise and with adequate carbohydrate consumption, muscle glycogen is rapidly resynthesised to near pre-exercise levels within 24 hours. Muscle glycogen then increases very gradually to above-normal levels over the next few days. Contributing to the rapid phase of glycogen resynthesis is an increase in the percentage of glycogen synthase I, an increase in the muscle cell membrane permeability to glucose, and an increase in the muscle's sensitivity to insulin. The slow phase of glycogen synthesis appears to be under the control of an intermediate form of glycogen synthase that is highly sensitive to glucose-6-phosphate activation. Conversion of the enzyme to this intermediate form may be due to the muscle tissue being constantly exposed to an elevated plasma insulin concentration subsequent to several days of high carbohydrate consumption. For optimal training performance, muscle glycogen stores must be replenished on a daily basis. For the average endurance athlete, a daily carbohydrate consumption of 500 to 600g is required. This results in a maximum glycogen storage of 80 to 100 mumol/g wet weight.(ABSTRACT TRUNCATED AT 400 WORDS)
TESTOSTERONE - PHYSIOLOGY AND FACTORS AFFECTING SERUM CONCENTRATION
David Woodhouse: MSc Sports Science
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5. Insulin
Insulin is a hormone secreted from the beta cells of the Islets of Langerhans in the pancreas. Its secretion is influenced by a number of factors but most significantly by high plasma glucose concentration. It promotes cellular uptake of glucose and amino acids and inhibits protein degradation (11). Elevation in blood insulin above 'baseline' levels causes a decrease in serum T. There is however, no correlation between insulin elevation and the degree of T decrease. The decreased serum T is believed to occur due to an increase in utilisation at muscle cells rather than a decrease in secretion. Supporting evidence to this theory includes LH concentration, which remain unaffected by elevated insulin (1). The popular idea of consuming large amounts of protein and carbohydrate post exercise to take advantage of elevated serum T therefore appears to be correct.
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