ABSTRACT
Blood glutamine levels are important for ensuring the proper development of mammalian organisms because glutamine acts as a potent precursor for biosynthetic processes/reactions and is a metabolic signal. In many pathological conditions, blood glutamine levels may vary with considerable consequences, particularly for immune response and regeneration in cases of decrease. The liver plays a central role in maintaining proper blood glutamine concentrations. In principle, this organ can either supply or take up glutamine via net production or net consumption. It has been revealed that morphogenic signals are master regulators of liver glutamine and ammonia metabolism. The chapter reviews basic findings concerning the regulation of liver glutamine metabolism by morphogens. Hepatic glutamine metabolism is affected by various types of signals. Metabolic cues, including ammonia levels, glutamate and alpha-oxoglutarate concentrations, pH, and several amino acids, act on the level of transporters and enzymes by modulating the activity of these proteins.
