Time‐dependent effects of fatty acids on skeletal muscle metabolism

Abstract

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.

Regulação do metabolismo de glicose e ácido graxo no músculo esquelético durante exercício físico

“…Dessa forma, a UCP-3 protege as mitocôndrias contra o acúmulo de AG na matriz. Essa hipótese é suportada pelas observações de que a UCP-3 é up-regulada em situações em que a disponibilidade de AG excede sua capacidade de oxidação, incluindo jejum, dieta hiperlipídica, tratamento com hormônios tireoidianos e exercício físico agudo, ao passo que a UCP-3 é down--regulada em situações nas quais a capacidade de oxidar AG é aumentada incluindo treinamento aeróbio e redução da massa corporal (43). Em adição, a expressão elevada de UCP-3 em músculos do tipo II, comparado a músculo do tipo I, é consistente com essa hipótese, uma vez que esse tipo de músculo apresenta baixa capacidade de oxidar lipídios (44).…”

The Effects of Palmitate on Hepatic Insulin Resistance Are Mediated by NADPH Oxidase 3-derived Reactive Oxygen Species through JNK and p38MAPK Pathways

“…Insulin resistance, defined as a diminished ability of cells, such as adipocytes, skeletal muscle cells, and hepatocytes, to respond to the action of insulin, plays a central role in the development of several metabolic abnormalities and diseases, such as obesity, type 2 diabetes, and the metabolic syndrome (2,3).…”

“…It has been suggested that increased reactive oxygen species (ROS) 3 levels are an important trigger for insulin resistance (7). Enhanced ROS production can lead to abnormal changes in intracellular signaling and development of insulin resistance (8).…”

miR-200s Contribute to Interleukin-6 (IL-6)-induced Insulin Resistance in Hepatocytes

“…Insulin resistance, defined as a diminished ability of cells, such as adipocytes, skeletal muscle cells, and hepatocytes, to respond to the action of insulin, plays a central role in the development of several metabolic abnormalities and diseases, such as obesity, type 2 diabetes, and the metabolic syndrome (1,2). Decreased glycogen levels are the hallmark of insulin resistance in the hepatocytes.…”