The relationship between adenine nucleotide metabolism and ischemic damage was studied in human liver. Thirty transplanted grafts were divided into two groups according to their functional outcome. Cellular adenine nucleotide levels were assayed by high-performance liquid chromatography. During cold ischemia, the adenosine triphosphate (ATP) level was not correlated with graft function, but two grafts with low total adenine nucleotides (TAN) levels showed poor function after transplantation. After recirculation, the ATP level showed good recovery in grafts that functioned satisfactorily (n = 24, 5.47 +/- 1.51 mumol/g dry weight), but remained low in poorly functioning grafts (n = 6, 3.30 +/- 1.68 mumol/g dry weight) (P less than 0.01). The level of recovery of ATP was inversely related to the period of warm ischemia during implantation (P less than 0.01). Bile production, used as a parameter of initial function, was observed shortly after implantation in 17 of 24 grafts that functioned satisfactorily, but in only 1 of 6 poorly functioning grafts. It is concluded that loss of adenine nucleotides and lack of bile production during transplantation are good markers of damaged grafts in human liver transplantation.