Pharmacokinetic analysis of I-123-labeled medium chain fatty acid as a radiopharmaceutical for hepatic function based on beta-oxidation

Beta-oxidation is the most important pathway to provide energy for the live r. Our recent findings indicated that radiolabeled medium chain fatty acid analogs could be used as radiopharmaceuticals in the liver, allowing us to monitor alterations in energy metabolism on the cellular level. In the pres ent study, pharmacokinetical analysis of a radioiodinated medium chain fatt y acid analog, p-[I-123]iodophenylenanthic acid ([I-123]IPEA), was carried out in normal and hepatitis model rats to investigate the index for the mea surement of beta-oxidation activity in hepatocytes. The rate constant for m etabolism of [I-123]IPEA in the liver showed a strong correlation with the ATP level, which was determined as an indicator of beta-oxidation activity in hepatocytes. The radioactivity profile in the liver after [I-123]IPEA ad ministration provided important information regarding hepatic viability, an d the metabolic rate constant of [I-123]IPEA calculated by a pharmacokineti c method was a useful criterion for hepatic diagnosis based on hepatic cell ular energy metabolism.