STUDIES ON DISTRIBUTION AND ELIMINATION OF [3H8] PYRIDOXINE IN MICE

[3H8] Pyridoxine has been administered by i.v. injection to mice, and the concentration of isotope has been determined in different tissues up to 30 days after the administration. An initial high uptake was found in all tissues except brain. The concentration decreased rapidly during the first day after administration and then at a slow rate. The decrease of isotope concentration was more rapid in liver than in muscle or carcass. The elimination of the vitamin from the body reservoir was estimated to be 7.9 per cent per day from day 1 to 30 compared to 6.5 per cent per day as calculated from the rate of excretion of isotope in the urine. One week after the administration of the isotope the concentration was approximately the same in heart, skeletal muscle, brain and kidney, and 20 % higher in liver. Between day 7 and 30 after the administration [3H8] pyridoxine 75% of the recovered isotope was found in carcass, 10–15% in liver and the remainder in other tissues. © 1969 Scandinavian Physiological Society