The Effects of alpha-Tocopherol on Mammalian Torpor

Abstract

Tocopherols (Vitamin E) are antioxidants that intercept the reactive oxygen species that initiate lipid peroxidation. Plants produce four tocopherol isomers, with α-tocopherol being the most biologically active. All mammals require tocopherols in their diets. Field and laboratory studies were conducted to determine the influence of diet α-tocopherol content on torpor by ground squirrels (Spermophilus lateralis). The diets of free-ranging ground squirrels contained both α and γ-tocopherols, with α-tocopherol being the most abundant. Natural diet atocopherol levels ranged from 1.5 to 34.1 µg/g. Laboratory experiments, however, revealed that squirrels fed diets with α-tocopherol contents above or below 12 µg/g were: 1) were less likely to enter torpor, and, 2) were less likely to survive torpor than those fed a diet containing 12 µg atocopherol/g. A low α-tocopherol diet is thus actually required for proper torpor.