Possible role of corticosterone in proteolysis, glycolytic, and amino acid metabolism in primary cultured avian myotubes incubated at high-temperature conditions

Abstract Excess glucocorticoid secretion induces oxidative damage and muscle proteolysis and modulates glucose and lipid metabolism. It is known that the high-temperature (HT) treatment enhances corticosterone (CORT) secretion, muscle proteolysis, and mitochondrial reactive oxygen species (mtROS) generation in chickens. The present study investigated the co-effects of CORT on proteolysis and mtROS production, together with glucose, fatty acid, and amino acid metabolism in HT-treated cells. Myoblast cells were isolated from the major pectoralis muscle of five 0- or 1-day-old neonatal chicks and were pre-cultured at 37°C/CO2 conditions for 48 h to reach sub-confluent (80%–90%) conditions. Cells were then reseeded onto a 6- or 24-well microplate for the subsequent measurement, followed by the culture under a control temperature (37°C, control) or HT (41°C) conditions for 1 or 6 h. The HT-treated cells were co-cultured with physiologically relevant concentrations of CORT (20 ng/mL in dimethyl sulfoxide). The HT treatment decreased cellular protein content (P