Oral theophylline changes renal carnitine palmitoyltransferase activity inrats

Background. Carnitine plays a critical role in lipid metabolism. Carnitine deficiency may adversely affect the oxidation of fatty acids and further ag gravate abnormal lipid metabolism. Our objective was to investigate the eff ect of theophylline on the activity of carnitine palmitoyltransferase (CPT) in renal tissues of rats for 5-week-interval treatments. Methods. The study was a randomized, controlled animal study. Theophylline was given at 100 mg/kg body weight (b.w.)/day and effects were monitored af ter a treatment period of between 1 and 5 weeks. Results. Theophylline treatment caused a significant increase in renal CPT activity as compared to either control or placebo groups. Moreover, the res ults showed positive correlations between the renal concentration of long-c hain acylcarnitine (LC), activity of CPT, urinary excretion of acylcarnitin e (AC), and plasma concentration of LC (p <0.01), respectively. Conclusions. The observed changes in activity of renal CPT might be due to the result from theophylline-enhanced mobilization of lipid from adipose ti ssues that consequently stimulated an increased carnitine transport into th e renal tissues to form palmitoylcarnitine groups for subsequent beta -oxid ation inside the mitochondria. Thus, these accumulations of palmitoylcarnit ine groups in mitochondria may increase the catalytic action of CPT. (C) 20 01 IMSS. Published by Elsevier Science Inc.