Cardiac membrane vitamin E and malondialdehyde levels in heart muscle of normotensive and spontaneously-hypertensive rats.
The vitamin E (alpha-tocopherol) and free and bound malondialdehyde (MDA) in ventricular heart muscle and myocardial membrane from Wistar-Kyoto (W/K) normotensive and spontaneously hypertensive (SH) rats have been measured directly by high performance liquid chromatography (HPLC). Thiobarbituric acid-reactive substance (TBA-RS) in the myocardium and heart-muscle membrane of the two strains was also quantified by a colorimetric TBA test. It was found that SH-rat myocardium and myocardial membrane contained more than 3-fold less alpha-tocopherol than did heart muscle and cardiac membrane of the normotensive rat. Coincident with this relative vitamin E deficiency were several-fold greater amounts of MDA and TBA-RS in SH-rat myocardium and myocardial membrane. Most (87%) of the MDA in SH-rat heart muscle, but only 40% in W/K-rat heart muscle, was free (i.e., unbound). These results offer direct evidence that SH-rat myocardium is vitamin E-deficient and highly peroxidative, relative to cardiac muscle of the normotensive W/K parent strain. The lower vitamin E content of SH-rat myocardium is particularly striking, because SH-rat myocardial membrane was found to contain approximately 35% more phospholipid than myocardial membrane in the W/K rat. Although the amounts of myocardial TBA-RS are greater in the SH strain, they do not reflect the actual MDA profiles of the heart muscles or the heart membranes and cannot be used as a quantitative index of cardiac oxidative-injury status due to non-MDA TBA-RS in both strains.
Janero
D R
DR
Department of Pharmacology and Chemotherapy, Roche Research Center, Hoffmann-La Roche Inc., Nutley, NJ 07110-1199.
Burghardt
B
B
D000818:Animals; D002462:Cell Membrane / Q000032:analysis*; D008314:Malonates / Q000032:analysis*; D008315:Malondialdehyde / Q000032:analysis*; D008563:Membrane Lipids / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis; D009206:Myocardium / Q000032:analysis* / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR / Q000378:metabolism*; D011919:Rats, Inbred Strains / Q000378:metabolism*; D011921:Rats, Inbred WKY; D014810:Vitamin E / Q000032:analysis*
D008314:Malonates; D008563:Membrane Lipids; D008565:Membrane Proteins; D014810:Vitamin E; D008315:Malondialdehyde