[Hormonal and pyridoxine induction of threonine dehydratase in the rat liver].

The activity of threonindehydratase in the liver of intact and adrenalectomized rats increased considerably after the administration of cortisol. A simultaneous with cortisol administration of insulin or testosterone led to inhibition of the corticosteroid induction of the enzyme. On the contrary, thyroxin increased both the basal activity of the enzyme and its response to the administration of cortisol. Besides the hormone, threonindehydratase cofactor (in the form of pyridoxine) led to an increase in the enzymatic activity. However, cofactor induction was expressed only in rats with intact adrenal glands.