Previous studies from this institution using human cell cultures have suggested that University of Wisconsin Solution may be preferred for prolonged cardiac storage. University of Wisconsin Solution (UWS) contains adenosine (5 mmole/liter) which could maintain adenine nucleotides better than other storage fluids. Human cardiomyocytes were isolated from left ventricular biopsies. Cells (seven to nine dishes/group) were rinsed of culture media and placed in one of four solutions: Stanford cardioplegia, phosphate-buffered saline, modified EuroCollins', or UWS. Metabolites were assessed using high-performance liquid chromatography (units = nmole/micrograms DNA) after 24 hr of storage at 0 degrees C and compared to baseline controls (BASE). Adenosine triphosphate (P less than 0.0001, ANOVA), adenosine diphosphate (P less than 0.0001), and adenosine monophosphate (P less than 0.01) decreased with each solution compared to BASE but were maintained best with UWS (P less than 0.05). Adenosine increased in the UWS cells only (BASE, 0.029 +/- 0.118; UWS, 1.836 +/- 1.110; P less than 0.0001, ANOVA). Adenosine in the UWS cells was largely degraded to inosine (UWS, 1.013 +/- 0.779; BASE, 0.034 +/- 0.032; P less than 0.0001) and hypoxanthine (UWS, 0.124 +/- 0.091; BASE, 0.005 +/- 0.005; P less than 0.001). University of Wisconsin Solution does preserve adenine nucleotides better than other storage fluids and may improve the clinical results of cardiac transplantation.