Abstract
1. A remarkable increase in urinary riboflavin and niacin was observed following an overdosage of thiamine or TAD to rabbits.
2. In this activity TAD was definitely greater than thiamine. In the former case the urinary excretion of riboflavin and niacin increased markedly followed by a pronounced decrease.
3. Following injections of 10mg/kg thiamine, the urinary excretion of riboflavin and pyridoxine was decreased, but following injections of 50mg/kg thiamine, the urinary excretion of both vitamins mentioned above rose at first, but fell distinctly.
4. The change in the urinary excretion of riboflavin parallelled roughly that of pyridoxine.
5. Following successive injections of 10.5mg/kg TAD, the urinary excretion of riboflavin and pyridoxine fell gradually.
6. Following successive injections of 52.5mg/kg TAD, the urinary excretion of riboflavin and pyridoxine showed a remarkable initial rise followed by a pronounced fall.
