Abstract
1 Ascorbic acid continued to arrest the oxidation process of tyrosine-tyrosinase system until it undergoes oxidation.
2. The efficiency as expressed in molar concentrations for inhibiting the formation of melanin was, in a decreasing order, as follows: glutathione, ascorbic acid, thiamine, lipoic acid. The lowest molar concentration of ascorbic acid needed for inhibition was 0.1×10-6M.
3. The skin ascorbic acid level is 1 in mormal persons and 5mg per 100g in rabbits. After intramuscular injection of 0.5g ascorbic acid the level was raised to 30 to 60mg per 100g in rabbits in 1 to 2 hours, consisting mostly of ascorbic acid rather than dehydroascorbic acid.
4. The highest level of blood ascorbic acid after repeated oral administration, 1g three times daily, was 2.6mg per 100ml.
5. Urinary exoretion of ascorbic acid was 10 to 20 per cent of the amounts administered. When 2g ascorbic acid was administered orally for 30 consecutive days, urinacy ascorbic acid in 24 hours on the 7th, 21st and 30th days did not show a marked increase.