The effects of prostaglandin E_1 (PGE_1) administered after relief of biliary obstruction, on liver energy metabolism in rats, were evaluated by 31^P-magnetic resonance spectroscopy (31^P-MRS). To assess the liver energy metabolism, the inorganic phosphate (Pi) and β-ATP peaks were monitored and analyzed by 31^P-MRS, 14 days after sham operation (group I, n=5) , 14 days after biliary obstruction (group II, n=5), 3 days after biliary decompression following 14 days-biliary obstruction