Investigations of the effects of theophylline administration on carnitine acetyltransferase activity of rat heart.
The effects of oral theophylline administration (100 mg/kg b.w./day) on the activity of carnitine acetyltransferase (CAT) of rat heart for five-week interval treatment were studied. The result indicated that the body weights of placebo groups were not significantly changed as compared to control groups (P < 0.1), but theophylline treatment caused a significant decrease in the body weights of rat (P < 0.01) as compared to either control or placebo groups throughout the five-week interval treatments. Daily administration of theophylline to rats did not significantly affect heart weights as compared to either control or placebo groups (P < 0.1) for the five week-interval treatments. Our data indicated that the activity of CAT was not significantly changed in placebo groups as compared to control groups (P < 0.1), however, there was a significant increase in the activity of CAT in heart of theophylline-treated groups (P < 0.01) as compared to either control or placebo groups. The increase in the activity of CAT was noticed in the first three weeks of theophylline treatments followed by a gradual return toward normal activity by the fourth and fifth weeks of continued treatment. The observed changes in activity of CAT of heart might be due to theophylline-enhanced mobilization of lipid from adipose tissues which consequently stimulated increased L-carnitine transport into the heart tissues to form fatty acyl-carnitine groups for subsequent beta-oxidation inside the heart mitochondria. Accumulations of acyl-carnitine groups in heart mitochondria may increase the catalytic action of CAT and possible mechanisms are discussed.
Alhomida
A S
AS
Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia. f40i002@ksu.edu.sa
D000818:Animals; D002332:Carnitine O-Acetyltransferase / Q000378:metabolism*; D004334:Drug Administration Schedule; D004789:Enzyme Activation / Q000187:drug effects; D007441:Intubation, Gastrointestinal; D008297:Male; D009206:Myocardium / Q000201:enzymology* / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013806:Theophylline / Q000008:administration & dosage / Q000494:pharmacology*
D013806:Theophylline; D002332:Carnitine O-Acetyltransferase