It appears that with overweight follows a slight decrease in muscle protein synthesis. This would in practice imply that with an increase of body-fat follows a reduced impact of exercise on the body’s adaptability and response in compensation to stimulus and to rebuild muscle tissue. But it also implies the opposite, that a decrease of body fat allows for an increase in the bodily functions to improve in the adaptability of exercising.
To investigate the sequential changes of protein synthesis in skeletal muscle during the establishment of obesity, considering muscle typology.
Adult Wistar rats were fed a standard diet during 16 weeks (C; n=14), or with a high-fat, high-sucrose diet during 16 (HF16; n=14) or 24 weeks (HF24; n=15). Body composition was measured using a dual-energy-x-ray absorptiometry scanner. The fractional synthesis rates (FSR) of muscle protein fractions were calculated in tibialis anterior (TA) and soleus muscles by incorporation of 1-13C-Valine in muscle protein. Muscle lipid and mitochondria contents were determined using histochemical analysis.
Obesity occurred in an initial phase, from 1 to 16 weeks, with an increase in weight (P
Muscle mass, lipid infiltration and muscle protein synthesis were differently affected, depending on the stage of obesity development and muscle typology. Chronic lipid infiltration in glycolytic muscle is concomitant with a reduction of muscle protein synthesis, suggesting that muscle lipid infiltration in response to high-fat diet is deleterious for the incorporation of amino acid in skeletal muscle proteins.
J Physiol. 2012 Jul 16. Time-course changes of muscle protein synthesis associated with obesity-induced lipotoxicity.