Hyperammonemia in gene-targeted mice lacking functional hepatic glutamine synthetase.

Impaired novelty acquisition and synaptic plasticity in congenital hyperammonemia caused by hepatic glutamine synthetase deficiency

Genetic defects in ammonia metabolism can produce irreversible damage of the developing CNS causing an impairment of cognitive and motor functions. We investigated alterations in behavior, synaptic plasticity and gene expression in the hippocampus and dorsal striatum of transgenic mice with systemic hyperammonemia resulting from conditional knockout of hepatic glutamine synthetase (LGS-ko). The...

Functional hyperactivity of hepatic glutamate dehydrogenase as a cause of the hyperinsulinism/hyperammonemia syndrome: effect of treatment.

OBJECTIVE The combination of persistent hyperammonemia and hypoketotic hypoglycemia in infancy presents a diagnostic challenge. Investigation of the possible causes and regulators of the ammonia and glucose disposal may result in a true diagnosis and predict an optimum treatment. PATIENT Since the neonatal period, a white girl had been treated for hyperammonemia and postprandial hypoglycemia ...

Biochemical and molecular analysis of glutamine synthetase gene in brassica napus L.

Pathological Role for Exocytotic Glutamate Release from Astrocytes in Hepatic Encephalopathy

Liver failure can lead to generalized hyperammonemia, which is thought to be the underlying cause of hepatic encephalopathy. This neuropsychiatric syndrome is accompanied by functional changes of astrocytes. These glial cells enter ammonia-induced self-amplifying cycle characterized by brain oedema, oxidative and osmotic stress that causes modification of proteins and RNA. Consequently, protein...

Influence of glutamine synthetase gene polymorphisms on the development of hyperammonemia during valproic acid-based therapy

PURPOSE Valproic acid (VPA), which is widely used to treat epilepsy, migraine, and bipolar disorder, can causes severe hyperammonemia. However, the mechanism responsible for this adverse effect is not readily apparent. We previously reported that phenytoin coadministration is a strong risk factor for the development of hyperammonemia during VPA-based therapy. In this study, we focused on glutam...