Cold acclimation in chickens increased suppression of palmitate-induced uncoupling by carboxyatractylate and increased mRNA levels of avANT and avUCP in skeletal muscle.
Cold acclimation in chickens increases avANT and avUCP mRNA expression, suggesting their involvement in the regulation of non-shivering thermogenesis in skeletal muscle.
Although bird species studied thus far have no distinct brown adipose tissue (BAT) or a related thermogenic tissue, there is now strong evidence that non-shivering mechanisms in birds may play an important role during cold exposure. Recently, increased expression of the duckling homolog of the avian uncoupling protein (avUCP) was demonstrated in cold-acclimated ducklings Raimbault et al., Biochem. J. 353 (2001) 441-444. Among the mitochondrial anion carriers, roles for the ATP/ADP antiporter (ANT) as well as UCP variants in thermogenesis are proposed. The present experiments were conducted (i) to examine the effects of cold acclimation on the fatty acid-induced uncoupling of oxidative phosphorylation in skeletal muscle mitochondria and (ii) to clone the cDNA of UCP and ANT homologs from chicken skeletal muscle and study differences compared to controls in expression levels of their mRNAs in the skeletal muscle of cold-acclimated chickens. The results obtained here show that suppression of palmitate-induced uncoupling by carboxyatractylate was greater in the subsarcolemmal skeletal muscle mitochondria from cold-acclimated chickens than that for control birds. An increase in mRNA levels of avANT and, to lesser degree, of avUCP in the skeletal muscle of cold-acclimated chickens was also found. Taken together, the present studies on cold-acclimated chickens suggest that the simultaneous increments in levels of avANT and avUCP mRNA expression may be involved in the regulation of thermogenesis in skeletal muscle.
Toyomizu et al. (Tue,) conducted a other in Cold acclimation in chickens. Cold acclimation vs. Control birds was evaluated on Fatty acid-induced uncoupling of oxidative phosphorylation and mRNA expression of avUCP and avANT. Cold acclimation in chickens increased suppression of palmitate-induced uncoupling by carboxyatractylate and increased mRNA levels of avANT and avUCP in skeletal muscle.