VITAMIN-E LEVELS AND SUSCEPTIBILITY TO LIPID-PEROXIDATION INCREASE WITH AGING IN HEART PLASMA-MEMBRANE FROM MINIATURE SWINE

Age-related changes in heart plasma membrane fatty acid composition, v itamin E content, membrane fluidify, susceptibility to lipid peroxidat ion, and the subcellular distribution of vitamin E: were observed in m erle and female Hormel-Hanford miniswine over a wide range of ages: pr epubertal, <0.5 years; young, 0.5-2.5 years; middle-aged, 5.9-10 years ; and old, 11.5-13.9 years. Pigs were continuously fed the same low-fa t, cholesterol-free, vitamin E-adequate stock diet at restricted maint enance levels. Membrane lipid peroxidation tended to increase in middl e-aged and elderly pigs, but not significantly, perhaps being somewhat ameliorated by the significantly increased membrane vitamin E in midd le-aged and old pigs. Mid-bilayer membrane fluidity was significantly increased in old pigs, but fluidity of the polar headgroup domains dec reased with age. Thus, lipid peroxidation tended to increase over the long life span of miniswine even when they are food restricted.