31P-topical nuclear magnetic resonance (31P-TMR) studies of cardiotoxic effects of 5-fluorouracil (5-FU) and 5'-deoxy-5-fluorouridine (5'-DFUR).

Abstract

Using the 31P-topical NMR method (TMR), an attempt was made to determine the myocardial high-energy phosphate compounds (HEP) contents under in situ conditions in closed-chest animals [guinea pigs], and the effects of opening the thorax on the myocardial energy metabolism were studied comparing the cardiotoxic effects of 5-fluorouracil (5-FU) in closed-chest and open-chest animals. The depletion of myocardial HEP produced by 5-FU was much more marked in open-chest animals than in closed-chest ones, indicating the necessity of conducting the experiments in closed-chest animals for the proper evaluation of the cardiotoxicity of certain types of compounds. The cardiotoxicity of a prodrug of 5-FU was assessed in closed-chest animals, and it was less cardiotoxic than 5-FU.