Exp Physiol. 2021 Mar 6. doi: 10.1113/EP089431. Online ahead of print.
ABSTRACT
NEW FINDINGS: What is the central question of this study? To explore the relationship between proteins in skeletal muscle and adipose tissue determined at rest and peak rates of fat oxidation in men and women. What is the main finding and its importance? Resting content of proteins in skeletal muscle involved in triglyceride hydrolysis and mitochondrial lipid transport are more strongly associated with peak fat oxidation rates than proteins related to lipid transport, or hydrolysis in adipose tissue. Whilst females display higher relative rates of fat oxidation than males, this was unexplained by the proteins measured in this study, suggesting other factors determine sex-differences in fat metabolism.
ABSTRACT: This study explored key proteins involved in fat metabolism that may associate with peak fat oxidation (PFO) and account for sexual dimorphism in exercise fuel metabolism. Thirty-six healthy adults [15 females; age 40 (11); V̇O2 peak 42.5 (9.5) mL⋅kg BM-1 ⋅min-1 ; means±SD] completed two exercise tests to determine PFO via indirect calorimetry. Resting adipose tissue and/or skeletal muscle biopsies were obtained to determine the protein content of adipose tissue PLIN1, CGI-58, HSL, ATGL, ACSL1, CPT1b and oestrogen receptor α (ERα), and skeletal muscle FABPpm, ATGL, ACSL1, CTP1b and ERα. Moderate strength correlations were found between PFO (mg⋅kg FFM-1 ⋅min-1 ) and the protein content of ATGL [rs = 0.41 (0.03-0.68), P<0.05] and CPT1b [rs = 0.45 (0.09-0.71), P<0.05] in skeletal muscle. No other statistically significant bivariate correlations were consistently found. Females had a greater relative PFO compared to males: 7.1±1.9 vs 4.5±1.3 and 7.3±1.7 vs 4.8±1.2 mg⋅kg FFM-1 ⋅min-1 )] in the adipose tissue (n = 14) and skeletal muscle (n = 12) sub-groups, respectively (p<0.05). No statistically significant sex differences were found in the content of these proteins. The regulation of PFO may involve processes relating to intramyocellular triglyceride hydrolysis and mitochondrial fatty acid transport, and adipose tissue is likely to play a more minor role than muscle. Sex differences in fat metabolism are likely to be due to factors other than the resting content of proteins in skeletal muscle and adipose tissue relating to triglyceride hydrolysis and fatty acid transport. This article is protected by copyright. All rights reserved.
PMID:33675111 | DOI:10.1113/EP089431
