Effect of dietary trans fatty acids on some membrane-associated enzymes and receptors in rat heart.
Three groups of male weanling Sprague-Dawley rats were fed diets containing 20% corn oil, 20% partially hydrogenated soybean oil (PHSBO) or 18% PHSBO + 2% corn oil. PHSBO contained about 48% of its total fatty acids as trans-octadecenoate. Rats were killed after 16-18 weeks of feeding the various diets, hearts were dissected and crude sarcolemma was prepared by differential centrifugation. The activities of ouabain-sensitive (Na+ + K+)ATPase were significantly lower in membranes of rats fed 20% PHSBO than the control rats fed 20% corn oil. The feeding of 2% corn oil with 18% PHSBO resulted in partial restoration of the enzyme activity. The maximum number of [3H]ouabain-binding sites (Bmax) was also lower in cardiac membranes of rats fed 20% PHSBO than those fed 20% corn oil. Similar to (Na+ + K+)-ATPase activity, some restoration of the number of [3H]ouabain-binding sites was observed when 2% corn oil was fed with 18% PHSBO-containing diet. There was no difference in the binding affinity of the radioligand for the receptor among the 3 dietary groups. Adenylate cyclase activities (fluoride-, isoproterenol- and forskolin-stimulated) were lower in membranes of rats fed 20% PHSBO or 18% PHSBO + 2% corn oil than in the control group fed 20% corn oil. Density of the beta-adrenergic receptor was the lowest in cardiac membranes of rats fed 20% PHSBO. The feeding of 2% corn oil with 18% PHSBO resulted in partial restoration of the maximum number of [3H]dihydroalprenolol (DHA)-binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)
Alam
S Q
SQ
Department of Biochemistry and Molecular Biology, Louisiana State University Medical Center, New Orleans 70119.
Ren
Y F
YF
Alam
B S
BS
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000201:enzymology* / Q000378:metabolism; D004041:Dietary Fats / Q000494:pharmacology*; D005227:Fatty Acids / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism; D009206:Myocardium / Q000032:analysis / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D004041:Dietary Fats; D005227:Fatty Acids; D008563:Membrane Lipids; D011943:Receptors, Adrenergic, beta; D000262:Adenylyl Cyclases; D000254:Sodium-Potassium-Exchanging ATPase