Specificity of Creatine in the Control of Muscle Protein Synthesis

Abstract

This study provides additional evidence that creatine, an end product of contraction unique to muscle, is involved in the control of muscle protein synthesis. Creatine is shown to stimulate selectively the rate of synthesis of two major contractile proteins, actin and myosin heavy chain, in cultures of differentiating skeletal muscle. Creatine affects only the rate of synthesis and not the rate of degradation. Several creatine analogs are as effective as creatine in stimulating muscle protein synthesis, creatinine and amino acids such as arginine and glycine are not. Creatine stimulates myosin heavy chain synthesis twofold in cultures of embryonic muscle grown in either normal or dialyzed media.

No effect of creatine supplementation on human myofibrillar and sarcoplasmic protein synthesis after resistance exercise

“…If it is the result of a direct effect of creatine, it should stimulate muscle protein synthesis or decrease muscle protein breakdown. Increased creatine availability has been reported in studies of animal skeletal and cardiac muscle in vitro to stimulate protein synthesis (15,16,33), although other investigators (11) were unable to confirm this.In starting to investigate the possible effects on human muscle, we began by studying the effect of creatine supplementation on human muscle protein turnover at rest in the fasted and fed conditions (20). In that study, we measured myofibrillar protein synthesis and leg protein breakdown in healthy young men before and after 5 days of dietary creatine supplementation sufficient to raise muscle total creatine concentration by 30%.…”

“…If it is the result of a direct effect of creatine, it should stimulate muscle protein synthesis or decrease muscle protein breakdown. Increased creatine availability has been reported in studies of animal skeletal and cardiac muscle in vitro to stimulate protein synthesis (15,16,33), although other investigators (11) were unable to confirm this.…”

Comparison of the novel compounds creatine and pyruvateon lipid and protein metabolism in broiler chickens

“…In this study, the expression of IGF-I gene was significantly increased in leg muscle in both the Cr-Pyr and Cr groups, and this was accompanied by increased relative leg muscle weight. The previous studies indicated that Cr may increase differentiation and protein synthesis in ovine myogenic satellite cells (Vierck, et al, 2003) and primary myotubes from chick embryos (Ingwall et al, 1974). In addition, several human studies have shown that Cr increases muscle protein (Balsom et al, 1995;Willoughby and Rosene, 2001;Deldicque et al, 2005).…”

Creatine supplementation has no effect on human muscle protein turnover at rest in the postabsorptive or fed states

“…If it is the result of creatine per se acting as a modulator of muscle mass, we can hypothesize that it should act either by stimulating muscle protein synthesis or by decreasing muscle protein breakdown. Increased creatine availability has been reported in studies of animal skeletal and cardiac muscle to stimulate protein synthesis (14,15,37), although others were unable to confirm this (10).Information concerning possible effects of creatine per se on protein metabolism in human beings is sparse. Part of the above hypothesis was tested by Parise et al (19), who measured mixed-muscle protein synthesis and whole body protein turnover in young sedentary subjects in the postabsorptive state after oral creatine supplements (20 g/day for 5 days followed by 5 g/day for 3-4 days).…”