Muscle, metabolism

Fatigue in Intact Skeletal Muscle of Human Subjects During High Intensity Exercise 247 Muscle Metabolism During Electrically Evoked High Intensity Contraction 248... 

It has been shown that inositol triphosphate (IP3) is involved in the excitation-contraction coupling in smooth muscle (Vergara et al., 1985), but presently no clear evidence has been reported for a similar involvement in skeletal muscle. If IP3 functions as a messenger for Ca release, it would bridge the gap between muscle metabolic changes and Ca release, as ATP is a prerequisite for IP3 regeneration. 

Muscle Metabolism During Electrically Evoked High Intensity Contraction... 

Asmussen, E. (1971). Muscle metabolism during exercise in man A historical survey. In Muscle Metabolism During Exercise (Pemow, B. Saltin, B., eds.), pp. 1-12. Plenum Press, New York. 

Boobis, L., Williams, C., Wootton, S.A. (1982). Human muscle metabolism during brief maximal exercise. J. Physiol. 338, 21-22 (Abstract). 

Hultman, E. Spriet, L.L. (1986). Skeletal muscle metabolism, contraction force and glycogen utilization during prolonged electrical stimulation in humans. J. Physiol. 374,493-501. 

Harris, J.B., Turnbull, D.M. (eds.). (1990), Muscle Metabolism. Balliere-Tindall, London. 

Figure 49-10. Simplified scheme of the causation of malignant hyperthermia (MIM 145600). At least 17 different point mutations have been detected in the RYRl gene, some of which are associated with central core disease (MIM 117000). It is estimated that at least 50% of families with members who have malignant hyperthermia are linked to the RYRl gene. Some individuals with mutations in the gene encoding DHPR have also been detected it is possible that mutations in other genes for proteins involved in certain aspects of muscle metabolism will also be found.

Various feamres of muscle metabolism, most of which are dealt with in other chapters of this text, are summarized in Table 49-12. 

Taegtmeyer, H., Roberts, A.F.C. and Raine, A.E.G. (1985). Energy metabolism in reperfused heart muscle Metabolic correlates to return of funaion. J. Am. Coll. Cardiol. 6, 864-870. 

Although the measurement of GFR with inulin is quite accurate, it is inconvenient because it requires the continuous infusion of this exogenous substance for several hours. More often, in clinical situations, the plasma clearance of creatinine is used to estimate GFR. Creatinine, an end-product of muscle metabolism, is released into the blood at a fairly constant rate. Consequently, only a single blood sample and a 24-h urine collection are needed. Measurement of the plasma clearance of creatinine provides only an estimate of GFR in fact, this measurement slightly overestimates it. A small amount of creatinine is secreted into the urine (about 10% on average). In other words, the concentration of creatinine in the urine is the result of the amount filtered (as determined by GFR) plus the amount secreted. 

Stoier S, Aaslyng M D, Olsen E V and Henckel P (2001), The effect of stress during lairage and stunning on muscle metabolism and drip loss in Danish pork , Meat Sci, 59, 127-131. 

Liver Minor protein stores helps muscle metabolize protein Muscle Major site of protein stores for metabolic needs Adipose No significant protein stores Red blood cells No significant protein stores Brain No significant protein stores... 

Sutherland, E.W. (1952). The effects of epinephrine and the hyperglycemic factor on liver and muscle metabolism in vitro. In Phosphorus Metabolism. (McElroy, W.D. Glass, B., Eds.), Vol. 2, pp. 577-593. The Johns Hopkins Press, Baltimore. 

In the next 2 to 3 years further experiments, particularly by Eggleston, who had joined Krebs in January 1936, confirmed and extended the observations. Careful quantitative evaluation of the data indicated that citrate like fumarate (Szent-Gyorgi) and like ornithine in the urea cycle exerted a catalytic effect on muscle metabolism. If arsenite, which blocks 2-oxoglutarate oxidation, was added with citrate to a respiring pigeon-muscle preparation, 2-oxoglutarate accumulated. 

Valine (Val or V) ((5)-2-amino-3-methyl-butanoic acid) is a nonpolar, neutral, aliphatic amino acid with the formula HOOCCH(NH2)CH(CH3)2. Along with Leu and He, Val is a branched-chain amino acid and is found in high concentrations in the muscles. Val is needed for muscle metabolism and coordination, tissue repair, and for the maintenance of proper nitrogen balance in the body. ° The steric hindrance present in Val and He (caused by branching) lowers the rate of coupling reactions, resulting in an increase in side reactions. ... 

Uric acid is the end product of the purine metabolism. When uric acid excretion via the kidneys is disturbed, gout can develop (see p. 190). Creatinine is derived from the muscle metabolism, where it arises spontaneously and irreversibly by cyclization of creatine and creatine phosphate (see p. 336). Since the amount of creatinine an individual excretes per day is constant (it is directly proportional to muscle mass), creatinine as an endogenous substance can be used to measure the glomerular filtration rate. The amount of amino acids excreted in free form is strongly dependent on the diet and on the ef ciency of liver function. Amino acid derivatives are also found in the urine (e.g., hippu-rate, a detoxification product of benzoic acid). 

Creatine (N-methylguanidoacetic acid) and its phosphorylated form creatine phosphate (a guanidophosphate) serve as an ATP buffer in muscle metabolism. In creatine phosphate, the phosphate residue is at a similarly high chemical potential as in ATP and is therefore easily transferred to ADP. Conversely, when there is an excess of ATP, creatine phosphate can arise from ATP and creatine. Both processes are catalyzed by creatine kinase [5]. 

D. Longrois, P. Menu, Resuscitation of severe but brief haemorrhagic shock with PFC in rabbits restores skeletal muscle oxygen delivery and does not alter skeletal muscle metabolism. Resuscitation 70 (2006) 124-132. 

Non-invasive P MRS has become one of the most useful tools to investigate in vivo muscle metabolism since the first muscle P MRS study reported by Hoult et al. in 1974. Many muscle P MRS studies in human or animal models have been reported and reviewed. For example, recently Kemp and his co-workers reported a quantitative review of phosphorus metabolite concentrations in human muscle. Here, we... 

E. Phielix and M. Mensink, Type 2 diabetes mellitus and skeletal muscle metabolic function. Physiol. Behav., 2008, 94,252-258. 

G. H. Raymer, H. J. Green, D. A. Ranney, G. D. Marsh and R. T. Thompson, Muscle metabolism and acid-base status during exercise in forearm work-related myalgia measured with 31P-MRS. /. Appl. Physiol., 2009,106,1198-1206. 

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