Brain beta-endorphin concentrations in experimental chronic liver disease

β-Endorphin, Met-enkephalin, substance P and somatostatin concentrations have been evaluated in brain areas of rats with severe liver disease obtained by chronic pretreatment with CCl4 for 3 or 9 weeks. β-Endorphin, but not Met-enkephalin, somatostatin or substance P concentrations were significantly decreased in the hypothalamus of both the three and nine week-treatment groups. The β-endorphin decrease we observed might be tentatively attributed to a modification of GABA levels, but not serotonin, since the stimulation of the serotoninergic system induced a significant increase, while the potentiation of the GABAergic system induced a clear decrease of β-endorphin concentrations in the hypothalamus of treated rats.