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The rate of adaptation of urea cycle enzymes, aminotransferases and glutamic dehydrogenase to changes in dietary protein intake

Published online by Cambridge University Press:  24 July 2007

T. K. Das  and
J. C. Waterlow
T. K. Das
Affiliation:
Department of Human Nutrition, London School of Hygiene and Tropical Medicine, Keppel Street (Gower Street), LondonWC1E 7HT
J. C. Waterlow
Affiliation:
Department of Human Nutrition, London School of Hygiene and Tropical Medicine, Keppel Street (Gower Street), LondonWC1E 7HT
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Abstract

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1. Measurements were made, at 6 h intervals, of urinary nitrogen output and of the activity of some hepatic enzymes in the rat during adaptation from one level of dietary protein to another. The enzymes measured were arginase (EC 3.5.3.1), argininosuccinate lyase (EC 4.3.2.1), argininosuccinate synthetase (EC 6.3.4.5), glutamate dehydrogenase (EC 1.4.1.2) and alanine and aspartate aminotransferases (EC 2.6.1.2 and EC 2.6.1.1).

2. Completeness of urine collection, which was essential for these experiments, was checked by recovery of injected [131I]iodide.

3. When the dietary protein content was reduced from 135 to 45 g casein/kg, the urinary N output and the activities of the hepatic enzymes reached their new steady-state levels in 30 h. The reverse adaptation, from 45 to 135 g casein/kg, was also complete in 30 h.

4. The rate of change of enzyme activity and the final activity as percentage of initial activity were very similar for all six enzymes, suggesting a common control mechanism. The calculated half-lives of the enzymes were of the order of 7 h, which is very much shorter than those found by previous workers.

5. There was no simple relationship between the activity of the urea cycle enzymes and the amount of N excreted. When an equal amount of gelatin was substituted for casein the N output was doubled but there was no change in the activity of the liver enzymes.

6. The results suggest that the activity of the urea cycle enzymes depends in part on the amount of N available for excretion after the demands for synthesis have been met. The enzymes, however, appear to be present in excess so that an increased N load was not necessarily accompanied by an increase in enzyme activity.

Type
General Nutrition
Information
British Journal of Nutrition , Volume 32 , Issue 2 , September 1974 , pp. 353 - 373
Copyright
Copyright © The Nutrition Society 1974

References

REFERENCES

Archibald, R. M. (1945). J. biol. Chem. 157, 507.CrossRefGoogle Scholar
Ashida, K. & Harper, A. E. (1961). Proc. Soc. exp. Biol. Med. 107, 151.CrossRefGoogle Scholar
Bergmeyer, H. U. (1963). Methods of Enzymic Analysis p. 11. New York: Academic Press.Google Scholar
Brown, G. W., Brown, W. R. & Cohen, P. P. (1959). J. biol. Chem. 234, 1775.CrossRefGoogle Scholar
Brown, G. W. & Cohen, P. P. (1959). J. biol. Chem. 234, 1769.CrossRefGoogle Scholar
Chan, H. (1968). Br. J. Nutr. 22, 315.CrossRefGoogle Scholar
Das, T. K. (1972). Proc. Nutr. Soc. 31, 78A.Google Scholar
Fisher, H. (1965). J. Nutr. 85, 181.CrossRefGoogle Scholar
Folin, O. (1905). Am. J. Physiol. 13, 66.CrossRefGoogle Scholar
Freedland, R. A. (1968). Life Sci. 7, part 2, 499.CrossRefGoogle Scholar
Gaetani, S., Paolucci, A. M., Spadoni, M. A. & Tomassi, G. (1964). J. Nutr. 84, 173.CrossRefGoogle Scholar
Gopalan, C. & Narasinga Rao, B. S. (1966). J. Nutr. 90, 213.CrossRefGoogle Scholar
Harper, A. E. (1965). Can. J. Biochem. Physiol. 43, 1589.Google Scholar
Inoue, H. & Pitot, H. C. (1970). Adv. Enzyme Regulation 8, 289.CrossRefGoogle Scholar
Kenney, F. T. (1970). In Mammalian Protein Metabolism Vol. 4, p. 131 [Munro, H. N., editor]. New York: Academic Press.CrossRefGoogle Scholar
Kiriyama, S. & Iwao, H. (1969). Agric. biol. Chem. J. 33, 1483.CrossRefGoogle Scholar
Kumar, I., Land, D. G. & Boyne, A. W. (1959). Br. J. Nutr. 13, 320.CrossRefGoogle Scholar
McLean, P. & Gurney, M. W. (1963). Biochem. J. 87, 96.CrossRefGoogle Scholar
Martin, C. J. & Robison, R. (1922). Biochem. J. 16, 407.Google Scholar
Millward, D. J. (1970). Clin. Sci. 39, 577.CrossRefGoogle Scholar
Muramatsu, K. & Ashida, K. (1962). J. Nutr. 76, 143.CrossRefGoogle Scholar
Muramatsu, K. & Nakagawa, T. (1971). Agric. biol. Chem. J. 35, 1594.CrossRefGoogle Scholar
Payne, P. R. & Stewart, R. J. C. (1972). Lab. Anim. 6, 135.CrossRefGoogle Scholar
Pitot, H. C., Potter, V. R. & Morris, H. P. (1961). Cancer Res. 21, 1001.Google Scholar
Rosen, F., Roberts, N. R. & Nicol, C. A. (1959). J. biol. Chem. 234, 476.CrossRefGoogle Scholar
Schimke, R. T. (1962). J. biol. Chem. 237, 459.CrossRefGoogle Scholar
Schimke, R. T. (1963). J. biol. Chem. 238, 1012.CrossRefGoogle Scholar
Schimke, R. T. (1964). J. biol. Chem. 239, 3808.CrossRefGoogle Scholar
Schimke, R. T. (1970). In Mammalian Protein Metabolism Vol. 4, p. 177 [Munro, H. N., editor]. New York: Academic Press.CrossRefGoogle Scholar
Scrimshaw, N. S., Hussein, M. A., Murray, E., Rand, W. M. & Young, V. R. (1972). J. Nutr. 102, 1595.CrossRefGoogle Scholar
Segal, H. L. & Kim, Y. S. (1963). Proc. natn. Acad. Sci. U.S.A. 50, 912.CrossRefGoogle Scholar
Stephen, J. M. L. (1968). Br. J. Nutr. 22, 153.CrossRefGoogle Scholar
Stephen, J. M. L. & Waterlow, J. C. (1968). Lancet i, 118.CrossRefGoogle Scholar
Szepesi, B. & Freedland, R. A. (1967). J. Nutr. 93, 301.CrossRefGoogle Scholar
Szepesi, B. & Freedland, R. A. (1969). Life Sci. 8 part 2, 1067.CrossRefGoogle Scholar
Technicon Instruments Corporation (1967). Technicon Methods Sheet N 3b. New York: Technicon Instruments Co.Google Scholar
Virden, R. (1972). Biochem. J. 127, 503.CrossRefGoogle Scholar
Waterlow, J. C. (1968). Lancet ii, 1091.CrossRefGoogle Scholar
Waterlow, J. C. & Patrick, S. J. (1954). Ann. N. Y. Acad. Sci. 57, 750.CrossRefGoogle Scholar
Waterlow, J. C. & Stephen, J. M. L. (1967). Clin. Sci. 33, 489.Google Scholar
Waterlow, J. C., Neale, R. J., Rowe, L. & Palin, I. (1972). Am. J. clin. Nutr. 25, 371.CrossRefGoogle Scholar
Wixom, R. L., Reddy, M. K. & Cohen, P. P. (1972). J. biol. Chem. 247, 3684.CrossRefGoogle Scholar
Wootton, I. D. P. (1964). Micro-analysis in Medical Biochemistry. London: Churchill.Google Scholar