Search Results
You are looking at 1 - 2 of 2 items for
- Author or Editor: C. Winkler x
- Refine by Access: All Content x
Abstract
Myocardial uptake and turnover of 17-(123I)-iodoheptadecanoic acid, injected i.v., was studied in rats. Kinetics of radioactivity incorporated into myocardial tissue and heart lipids as well as myocardial radioactivity recovered as123I iodide were determined. Maximal heart uptake of IHA (7.9% dose/g heart) was observed as early as 30 sec., p.i., followed by mono-component elimination period. Already 10 to 30 sec p.i. 70 to 80% of total myocardial radioactivity was recovered as123I iodide. IHA was incorporated only in modest amounts into myocardial phospholipids and triglycerides. Time course of total myocardial radioactivity grossly paralleled that recovered as123I iodide. These findings indicate stringent limitations in utility of IHA as a tracer for assessment of β-oxidation.
Abstract
Uptake and turnover of chloroform/methanol extractable tissue lipids labelled in vivo simultaneously with 15/p-123I-phenyl-/pentadecanoic and l-14C-palmitic acid were compared. Lipid turnover studies were performed in fasted pentobarbital-anaesthetized Wistar rats in tissues with highly varying free fatty acid turnover rates. In all tissues investigated, i.e. heart, lung, liver, spleen and kidneys, both tracers labelled nearly identical lipid fraction. Main tracer uptake was found in free fatty acids, phospholipids, diglycerides and triglycerides. A highly significant correlation of uptake and turnover in main tissue lipid fraction indicated an essentially identical metabolic pathway of both tracers in intermediary tissue lipid metabolism. Concordant tracer uptake and turnover patterns in tissue of lipids with highly varying free fatty acid metabolic rates suggested that intrinsic metabolic activity of the tissue and respective lipid fraction was the major determinant of metabolic handling of both iodophenyl fatty- and palmitic acid. Thus, the feasibility of iodophenylpentadecanoic acid as free fatty acid tracer for studying tissue lipid metabolism is demonstrated.
