MSTN and Hyperammonemia: Furthermore, pharmacologic inhibition of NF-κB by pyrrolidine dithiocarbamic acid (PDA) abolished MSTN promoter upregulation in response to ammonium acetate and increased myotube diameter in vitro, indicating the important role Mstn promoter has on sarcopenia caused by hyperammonemia in cirrhosis and other hepatic malfunctions [36].