Abstract
Vitamin E deficiency of premature infant often induces hemolytic anemia and may be one of the factors resulting in bronchopulmonary dysplasia and retrolental flbroplasia by oxygen therapy. However, vitamin E is poorly absorbed from the gastrointestinal tract of premature infant, so it is necessary to administer vitamin E parenterally when it is required. The purpose of this investigation is to examine the bioavailability of parenterally administered vitamin E. When dl-α-tocopheryl acetate is administered parenterally to the dogs, it enters into the blood stream and then ten percent is hydrolyzed to α-tocopherol in liver and/or other organs. By intramuscular administration of dl-α-tocopheryl acetate (5 mgj/kg), plasma α-tocopherol levels indicated maximal increment of 5.2±3.1 μg/ml with a large individual difference. By intravenous administration of dl-α-tocopheryl acetate (5 mg/kg), plasma α-tocopherol levels indicated a maximal increment of 8.4±1.2 μg/ml without individual difference. However, more than eight hours were required to reach maximal increment of plasma α-tocopherol level, when dl-α-tocopherol acetate was administered parenterally. On the other hand, by intravenous administration of dl-α-tocopherol (5 mg/kg), a maximal increment of plasma α-tocopherol levels (115.2+27.5 μg/ml) and α-tocopherol levels in high density lipoprotein (62.6+11.9 μg/ml) was obtained just after injection. These results suggest that intravenous ad-ministration of dl-α-tocopherol is the most effective method to obtain rapid increment of plasma α-tocopherol levels.
