Potential Antiproteolytic Effects of L-leucine
Potential Antiproteolytic Effects of L-leucine
The purpose of present review is to describe the effect of leucine supplementation on skeletal muscle proteolysis suppression in both in vivo and in vitro studies. Most studies, using in vitro methodology, incubated skeletal muscles with leucine with different doses and the results suggests that there is a dose-dependent effect. The same responses can be observed in in vivo studies. Importantly, the leucine effects on skeletal muscle protein synthesis are not always connected to the inhibition of skeletal muscle proteolysis. As a matter of fact, high doses of leucine incubation can promote suppression of muscle proteolysis without additional effects on protein synthesis, and low leucine doses improve skeletal muscle protein ynthesis but have no effect on skeletal muscle proteolysis. These research findings may have an important clinical relevancy, because muscle loss in atrophic states would be reversed by specific leucine supplementation doses. Additionally, it has been clearly demonstrated that leucine administration suppresses skeletal muscle proteolysis in various catabolic states. Thus, if protein metabolism changes during different atrophic conditions, it is not surprising that the leucine dose-effect relationship must also change, according to atrophy or pathological state and catabolism magnitude. In conclusion, leucine has a potential role on attenuate skeletal muscle proteolysis. Future studies will help to sharpen the leucine efficacy on skeletal muscle protein degradation during several atrophic states.
Skeletal muscle atrophy is considered an important public health problem due to its primary (metabolic alterations) and secondary consequences (strength loss, decreased autonomy). As known, the atrophy process becomes apparent when skeletal muscle protein degradation is increased above protein synthesis during a prolonged period of time. In this context, leucine supplementation seems to be a promising anti-atrophy therapy, acting either by inhibiting skeletal muscle proteolysis and/or increasing protein synthesis, an effect which may possibly be both dose-dependent as well as skeletal muscle atrophy condition-dependent. This review will discuss the effects of leucine supplementation in the regulation of skeletal muscle proteolysis in both, in vitro and in vivo studies.
Abstract and Introduction
Abstract
The purpose of present review is to describe the effect of leucine supplementation on skeletal muscle proteolysis suppression in both in vivo and in vitro studies. Most studies, using in vitro methodology, incubated skeletal muscles with leucine with different doses and the results suggests that there is a dose-dependent effect. The same responses can be observed in in vivo studies. Importantly, the leucine effects on skeletal muscle protein synthesis are not always connected to the inhibition of skeletal muscle proteolysis. As a matter of fact, high doses of leucine incubation can promote suppression of muscle proteolysis without additional effects on protein synthesis, and low leucine doses improve skeletal muscle protein ynthesis but have no effect on skeletal muscle proteolysis. These research findings may have an important clinical relevancy, because muscle loss in atrophic states would be reversed by specific leucine supplementation doses. Additionally, it has been clearly demonstrated that leucine administration suppresses skeletal muscle proteolysis in various catabolic states. Thus, if protein metabolism changes during different atrophic conditions, it is not surprising that the leucine dose-effect relationship must also change, according to atrophy or pathological state and catabolism magnitude. In conclusion, leucine has a potential role on attenuate skeletal muscle proteolysis. Future studies will help to sharpen the leucine efficacy on skeletal muscle protein degradation during several atrophic states.
Introduction
Skeletal muscle atrophy is considered an important public health problem due to its primary (metabolic alterations) and secondary consequences (strength loss, decreased autonomy). As known, the atrophy process becomes apparent when skeletal muscle protein degradation is increased above protein synthesis during a prolonged period of time. In this context, leucine supplementation seems to be a promising anti-atrophy therapy, acting either by inhibiting skeletal muscle proteolysis and/or increasing protein synthesis, an effect which may possibly be both dose-dependent as well as skeletal muscle atrophy condition-dependent. This review will discuss the effects of leucine supplementation in the regulation of skeletal muscle proteolysis in both, in vitro and in vivo studies.
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