John C. Keresztesy

Urinary excretion of vitamin B6 in the rat.

Summary A colorimetric method for the determination of vitamin B6 has been used to study the urinary excretion of the vitamin in the rat. At high dose levels (10 mg per kg and above) 50 to 70% of the vitamin is excreted by both normal and deficient rats. The vitamin is rapidly and completely absorbed and is rapidly excreted. At low levels (2 mg per kg) the data are qualitative, but normal rats appear to excrete a higher percentage of the ingested vitamin than B6–deficient rats.

Biotin Deficiency in the Rat

Summary Synthetic pyridoxine is almost inactive as a growth factor for S. Zizctis Rin a pyridoxine-free medium if heat sterilization is avoided. Autoclaving media which contain pyridoxine greatly increases its activity for this organism. The same effect was achieved in varying degrees by autoclaving pyridoxine at neutrality with individual amino acids. Cystine and glycine were most effective in producing this change.

A Comparison of Some Methods for the Extraction of Vitamin B1 from International Standard Acid Clay

Summary A comparison of different methods of removing vitamin B1 from the international standard clay shows that the quinine sulfate method yields approximately twice the amount of vitamin that is obtained by alkaline extraction methods.