Hormonal and cofactor induction of tyrosine transaminase in vitamin B 6 deficiency

Abstract

The activity of liver tyrosine transaminase of vitamin B 6 deficient rats is approximately half that of normal animals. Administration of hydrocortisone to deficient animals raises the level of liver transaminase activity to a value 6 times greater than that achieved by the administration of pyridoxine. Actinomycin D or puromycin given with the vitamin or the hormone at zero time do not prevent the rise in enzymatic activity but further enhance it to values above the induced level. The results suggest that, in vitamin B 6 deficiency, cofactor and hormonal enzyme induction reflect stabilization of enzyme in vivo rather than de novo enzyme synthesis.