[Effect of substrate and small doses of cortisone on the induction of Tryptophan 2,3-dioxygenase (author's transl)].
Hoppe Seylers Z Physiol Chem, 1976/6;357(6):811-7.
PMID: 60273
Abstract
A number of enzymes are induced by steroid hormones. In this paper the reaction of tryptophan 2,3-dioxygenase is further analyzed. In particular we show in which way the substrate and low doses of cortisone cause an induction. 1) For the induction of tryptophan 2,3-dioxygenase in adrenalectomized rats by 2.5 mg cortisone/kg, the presence of the substrate is necessary as well. Under these conditions an induction of the enzyme can already be registered in the presence of 12.5 mg L-tryptophan/kg. 2) In animals treated before with cortisone, the enzyme maximum appears 30 min after L-tryptophan injection, The enhancement of enzyme activity in animals which are treated with 2.5 mg cortisone/kg before is blocked by actidione only until 30 min after L-tryptophan injection. 3) Experiments with antibodies in animals treated with a low dosis of cortisone show that L-tryptophan acts mainly via enzyme degradation or the saturation with the coenzyme hematin, respectively.
MeSH terms
Adrenalectomy; Animals; Antibodies; Arylformamidase; Cortisone; Enzyme Induction; Female; Leucine; Rats; Tryptophan; Tryptophan Oxygenase
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