Acute effect of exercise in the intensity of maximal lactate steady state on protein and mRNA expressions of HIF-1±, MCTs 1 e 4 e PGC-1±, in heart, hepatic and skeletal muscle of swimming rats

Abstract

In skeletal muscle the main monocarboxylic transporters (MCTs) responsible for lactate dynamism are the MCT1 and MCT4 isoforms, associated respectively to influx and eflux of lactate. It is known that physical stress plays a role in modulating the genic expression of MCTs by means of seemingly distinct molecular signaling pathways involving the co-activator peroxisome proliferator activated receptor gama 1 (PGC-1±) and the hipoxia inducible factor 1 (HIF-1), respectively. Only a single resistance exercise session (endurance) is associated with increased expression of MCT1 and PGC-1±, but not the MCT4 in the vastus lateralis of human skeletal muscle, while the high-intensity intermittent exercise seems to affect both MCTs 1 4 and the PGC-1±. However, the effects of physical stress on the skeletal muscle HIF-1± and its association with PGC-1± simultaneously with MCTs 1 and 4 in different fiber types are unknow. It is likely that expressions of both co-activators and transcription factors are affected and involved in the modulation of MCTs 1 and 4 during physical activity stress differently according to intensity and may vary according to the type and specificity of the examined tissue. Thus, the objective of this project is to verify the acute effect of exercise in the intensity of maximal lactate steady state on protein and mRNA expressions of HIF-1±, MCTs 1 e 4 e PGC-1±, in heart, hepatic and skeletal muscle of swimming rats.