Hyperprolactinemia in hepatic encephalopathy: the effect of infusion of an amino acid mixture with excess branched chain amino acids
Bauer, A.G.; Wilson, J.H.; Lamberts, S.W.; Blom, W.
Hepato-Gastroenterology 30(5): 174-177
1983
ISSN/ISBN: 0172-6390 PMID: 6416978 Document Number: 216621
Prolactin levels are elevated in patients with liver cirrhosis and hepatic encephalopathy. Patients with hepatic encephalopathy also have an abnormal plasma amino acid composition, with a relative excess of aromatic amino acids, and a relative decrease in branched chain amino acid levels. In order to study the effect of the plasma amino acid composition on prolactin release, we measured plasma PRL at 0, 10, 20, 30, 40, 50 and 60 minutes after 400 micrograms TRH, both after infusion of a conventional amino acid mixture and after a branched chain amino acid enriched mixture (BCAA) in 5 patients with cirrhosis of the liver and hepatic encephalopathy. After conventional amino acid infusion, a depressed branched chain/aromatic amino acid ratio was found in all patients, together with an increased PRL response to TRH. After BCAA infusion the branched chain/aromatic amino acid ratio normalized. At the same time the excessive PRL response to TRH stimulation was significantly lower in all patients. This suggests that the elevated PRL levels in hepatic encephalopathy are caused by a disturbance of hypothalamic neurotransmitter systems, due to altered amino acid-neurotransmitter precursor levels.