Time-dependent effects of fatty acids on skeletal muscle metabolism.
Increased plasma levels of free fatty acids (FFA) occur in states of insulin resistance such as type 2 diabetes mellitus, obesity, and metabolic syndrome. These high levels of plasma FFA seem to play an important role for the development of insulin resistance but the mechanisms involved are not known. We demonstrated that acute exposure to FFA (1 h) in rat incubated skeletal muscle leads to an increase in the insulin-stimulated glycogen synthesis and glucose oxidation. In conditions of prolonged exposure to FFA, however, the insulin-stimulated glucose uptake and metabolism is impaired in skeletal muscle. In this review, we discuss the differences between the effects of acute and prolonged exposure to FFA on skeletal muscle glucose metabolism and the possible mechanisms involved in the FFA-induced insulin resistance.
Hirabara
Sandro M
SM
Department of Physiology and Biophysics, University of São Paulo, São Paulo, SP, Brazil. sandromh@icb.usp.br
Silveira
Leornardo R
LR
Abdulkader
Fernando
F
Carvalho
Carla R O
CR
Procopio
Joaquim
J
Curi
Rui
R
D000818:Animals; D005230:Fatty Acids, Nonesterified / Q000378:metabolism* / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007333:Insulin Resistance; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D010085:Oxidative Phosphorylation / Q000187:drug effects; D019308:Palmitic Acid / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects*; D013997:Time Factors; D014475:Uncoupling Agents / Q000378:metabolism* / Q000494:pharmacology
D005230:Fatty Acids, Nonesterified; D007004:Hypoglycemic Agents; D007328:Insulin; D014475:Uncoupling Agents; D019308:Palmitic Acid; D006003:Glycogen; D005947:Glucose