Studies on Fatty Acid Esters of Flavins. Iv. Fate of Injected Fatty Acid Esters of Riboflavin in Rabbits
Yagi, K.; Okuda, J.; Matsubara, T.
Journal of Vitaminology 10: 275-283
For part 3 see Abst. 3961, Vol. 34. 4. Male rabbits of about 2.5 kg were given a diet of barley and vegetables for 1 week and were then tied and laid on a table for 24 h and given only cabbage, and 5 mg riboflavine in saline or the equivalent amount of riboflavine-2', 3', 4', 5'-tetrapalmitate or riboflavine-2', 3', 4', 5'-tetrabutyrate in salad oil was injected into the femoral muscle; samples of blood and urine were taken at intervals from 1 to 24 h later. Flavins were estimated in blood after removal of proteins by trichloroacetic acid, and in urine, by microfluorimetry (Abst. 1772, Vol. 27); flavins in urine were identified by paper chromatography. In 2 normal rabbits the flavin contents of blood and urine decreased with time. In 2 rabbits injected with 5 mg riboflavine they rapidly increased, reaching a maximum of 20 micro g per 100 ml and 98 micro g per ml, respectively, 1 h after injection, and returned to normal after 6 to 8 h. After 1 h 30% of the injected riboflavine was excreted in the urine and a further 30% within the next 5 h. When riboflavine tetrapalmitate was injected there was no increase in blood or urine within 24 h. Injection of riboflavine tetrabutyrate caused a gradual increase and then a slow decrease; 30 to 40% was excreted as free riboflavine within 24 h. P. Wilson.