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KMID : 0378019710140040101
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New Medical Journal
1971 Volume.14 No. 4 p.101 ~ p.106
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Effect of cycloheximide on tryptophan oxygenase induction in vivo and in vitro
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Lee Yong-Choo
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Abstract
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Tryptophan oxygenase(tryptophan : oxygen oxidoreductase, EC 1. 13. 1.12) in liver was increased several fold when tryptophan was administrated intraperitoneally into rats 6 hours prior to sacrifice (Knox and Mehler, 1951). This enzyme was also induced when rat liver slices were incubated with substrate in tissue culture medium containing amino acids (Civen and Knox, 1959).
On the other hand hormonal induction of this enzyme has not been feasible in vitro by simple incubating liver slices or homogenates with hormones in tryptophan pyrrolase assay medium. These experiments indicated that there were two types of inducing agents, the substrate and an hormone. In vitro induction of tryptophan pyrrolase has also been demonstrated by Gorden and Clouet (1959) when normal rat liver homogenate was incub￢ated in a complex medium prepared by these authors.
Recently, it has been considered that the induction of this enzyme by hormone and by tryptophan occurs by different mechanisms; the hormone effect is considered to require RNA synthesis, but the tryptophan effect is considered to occur without´ the need for synthesis of RNA (Greengard et al., 1963; Kroeger and Greuer, 1966; Valti-Nayg and Daroczy, 1967).
The present studies were undertaken to clarify whether the cycloheximide, an potent inhibitor of protein synthesis, might exert an inhibitory effect on in vivo as well as in vitro increments by substrate of tryptophan pyrrolase activity.
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