Porcine somatotropin decreases acetyl-CoA carboxylase gene expression in porcine adipose tissue.

Crossbred barrows were treated daily with porcine somatotropin (pST; 4 mg/d) from 79 to 127 kg BW to determine whether pST regulates the activity and gene expression of adipose tissue acetyl-CoA carboxylase (ACC), the rate limiting enzyme in de novo fatty acid synthesis. Administration of pST reduced ACC enzyme activity, protein content, and mRNA abundance in adipose tissue by 40 to 50%. When comparisons were made among all pigs, ACC enzyme activity and mRNA abundance were closely associated (r2 = .94). In summary, our results indicate that pST decreases ACC enzyme activity and that this is associated with a significant reduction in ACC mRNA abundance. We speculate that decreased ACC enzyme activity results from a reduction in ACC protein and that this occurs because pST reduces the abundance of mRNA available for translation.