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Science 19 June 1959:
Vol. 129. no. 3364, pp. 1672 - 1673
DOI: 10.1126/science.129.3364.1672
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Articles

Pattern of Adaptive Control of Levels of Rat Liver Tryptophan Transaminase

MORTON CIVEN 1 and W. EUGENE KNOX 1

1 Department of Biological Chemistry, Harvard Medical School, and Cancer Research Institute, New England Deaconess Hospital, Boston, Massachusetts

The dual control by substrate and hormone of the level of a third adaptive enzyme in animals is described. Injections of hydrocortisone or the substrate tryptophan increased the level of the liver tryptophan-agr-ketoglutarate transaminase of intact rats within 5 hours. In adrenalectomized rats this enzyme level was increased by hydrocortisone alone, but substrate induction could be demonstrated only if these animals were treated at the same time with hydrocortisone.

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Science. ISSN 0036-8075 (print), 1095-9203 (online)