UNASSIGNED: High-fat diets (HFDs) have been shown to interfere with skeletal muscle energy metabolism and cause peripheral insulin resistance. However, understanding of HFD impact on skeletal muscle primary function, i.e., contractile performance, is limited. Male C57BL/6J @entity19 were fed HFD containing lard (HFL) or palm oil (HFP), or low-fat diet (LFD) for 5weeks. Fast-twitch (FT) extensor digitorum longus (EDL) and slow-twitch (ST) soleus muscles were characterized with respect to contractile function and selected biochemical features. In FT EDL muscle, a 30%-50% increase in @entity844 (FA) content and doubling of long-chain @entity14992 (C14-C18) content in response to HFL and HFP feeding were accompanied by increase in protein levels of peroxisome proliferator-activated receptor-y coactivator-1a, mitochondrial oxidative phosphorylation complexes and @entity8595 dehydrogenases involved in mitochondrial FA b-oxidation. Peak force of FT EDL twitch and tetanic contractions was unaltered, but the @entity1054 ( @entity1054 ) of twitch contractions was 30% slower compared to LFD controls. The latter was caused by accumulation of lipid intermediates rather than changes in the expression levels of proteins involved in @entity460 handling. In ST soleus muscle, no evidence for lipid overload was found in any HFD group. However, particularly in HFP group, the peak force of twitch and tetanic contractions was reduced, but @entity1054 was faster than LFD controls. The latter was associated with a fast-to-slow shift in troponin T isoform expression. Taken together, these data highlight fiber-type-specific sensitivities and phenotypic adaptations to dietary lipid overload that differentially impact fast- versus slow-twitch skeletal muscle contractile function.

Fiber-type-specific sensitivities and phenotypic adaptations to dietary fat overload differentially impact fast- versus slow-twitch muscle contractile function in C57BL/6J XXXX .

@entity844 :: ('CHEBI:35366', 'Chemical') :: ['fatty acid'] @entity19 :: ('10090', 'Species') :: ['mice'] @entity14992 :: ('MESH:C116917', 'Chemical') :: ['acylcarnitine'] @entity8595 :: ('MESH:D000214', 'Chemical') :: ['acyl-CoA'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium'] @entity1054 :: ('MESH:D000377', 'Disease') :: ['RT', 'relaxation time']
@entity19 :: (10090,Species) :: ['mice']
