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Idiosyncratic nutrient requirements of cats appear to be diet-induced evolutionary adaptations*

Published online by Cambridge University Press:  14 December 2007

James G Morris
James G Morris*
Affiliation:
Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
*
Corresponding author: Dr James G. Morris, fax +1 530 752 4698, email jgmorris@ucdavis.edu
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Abstract

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Cats have obligatory requirements for dietary nutrients that are not essential for other mammals. The present review relates these idiosyncratic nutritional requirements to activities of enzymes involved in the metabolic pathways of these nutrients. The high protein requirement of cats is a consequence of the lack of regulation of the aminotransferases of dispensable N metabolism and of the urea cycle enzymes. The dietary requirements for taurine and arginine are consequences of low activities of two enzymes in the pathways of synthesis that have a negative multiplicative effect on the rate of synthesis. Cats have obligatory dietary requirements for vitamin D and niacin which are the result of high activities of enzymes that catabolise precursors of these vitamins to other compounds. The dietary requirement for pre-formed vitamin A appears to result from deletion of enzymes required for cleavage and oxidation of carotenoids. The n-3 polyunsaturated fatty acids (PUFA) requirements have not been defined but low activities of desaturase enzymes indicate that cats may have a dietary need for pre-formed PUFA in addition to those needed by other animals to maintain normal plasma concentrations. The nutrient requirements of domestic cats support the thesis that their idiosyncratic requirements arose from evolutionary pressures arising from a rigorous diet of animal tissue. These pressures may have favoured energy conservation through deletion of redundant enzymes and modification of enzyme activities to result in metabolites more suited to the cat's metabolism. However, this retrospective viewpoint allows only recognition of association rather than cause and effect.

Keywords

Nutrient requirementsProtein metabolismEnzyme adaptationCats
Type
Research Article
Information
Nutrition Research Reviews , Volume 15 , Issue 1 , June 2002 , pp. 153 - 168
Copyright
Copyright © CABI Publishing 2002

Footnotes

*

A preliminary presentation of some of the material in the present review was made as Morris (2001).

References

Alexis, MN & Papaparaskeva-Papoutsoglou, E (1986) Aminotransferase activity in the liver and white muscle of Mugil capito fed diets containing different levels of protein and carbohydrate. Comparative Biochemistry and Physiology 83B, 245–249.Google Scholar
Anderson, HL, Benevenga, NJ & Harper, AE (1968) Associations among food and protein intake, serine dehydratase, and plasma amino acids. American Journal of Physiology 214, 1008–1013.CrossRefGoogle ScholarPubMed
Anderson, PJB, Rogers, QR & Morris, JG (2002) Cats require higher dietary phenylalanine or tyrosine for melanin in hair than growth. In Journal of Nutrition 132 (In the Press).Google ScholarPubMed
Arai, T, Kawaue, T, Abe, M, Kuramoto, E, Kamakami, E, Sako, T & Washizu, T (1998) Comparison of glucokinase activities in the peripheral leukocytes between dogs and cats. Comparative Biochemistry and Physiology 120, 53–56.Google ScholarPubMed
Baker, DH & Speer, VC (1983) Protein-amino acid nutrition of nonruminant animals with emphasis on the pig: past, present and future. Journal of Animal Science 57, Suppl. 2, 248–299.Google ScholarPubMed
Ballard, FJ (1965) Glucose utilization in the mammalian liver. Comparative Biochemistry and Physiology 14, 437–443.CrossRefGoogle ScholarPubMed
Bauer, JE (1997) Fatty acid metabolism in domestic cats (Felis catus) and cheetahs (Acinonyx jubatas). Proceedings of the Nutrition Society 56, 1013–1024.CrossRefGoogle ScholarPubMed
Biourge, V, Groff, JM, Fisher, C, Bee, D, Morris, JG & Rogers, QR (1994) Nitrogen balance, plasma free amino acid concentrations and urinary orotic acid excretion during long-term fasting in cats. Journal of Nutrition 124, 1094–1103.CrossRefGoogle ScholarPubMed
Carey, GP, Kime, Z, Rogers, QR, Morris, JG, Hargrove, D, Buffington, CA & Brusilow, SW (1987) An arginine-deficient diet in humans does not evoke hyperammonaemia or orotic aciduria. Journal of Nutrition 117, 1734–1739.CrossRefGoogle ScholarPubMed
Chandra, M, Singh, B, Soni, GL & Ahuja, SP (1984) Renal and biochemical changes produced in broilers by high-protein, high-calcium, urea-containing, and vitamin A-deficient diets. Avian Diseases 28, 1–11.CrossRefGoogle ScholarPubMed
Chen, HY, Lewis, AJ, Miller, PS & Yen, JT (1999) The effect of excess protein on growth performance and protein metabolism of finishing barrows and gilts. Journal of Animal Science 77, 3238–3247.CrossRefGoogle ScholarPubMed
Costello, MJ, Morris, JG & Rogers, QR (1980) Effect of dietary arginine level on urinary orotate and citrate excretion in growing kittens. In Journal of Nutrition 110 1204–1208.CrossRefGoogle ScholarPubMed
Coulson, RA & Hernandez, T (1983) Alligator Metabolism. Studies on Chemical Reactions In Vivo. Oxford: UK: Pergamon Press.Google ScholarPubMed
Cowey, CB, Cooke, DJ, Matty, AJ & Adron, JW (1981) Effects of quantity and quality of dietary protein on certain enzyme activities of rainbow trout. Journal of Nutrition 111, 336–345.CrossRefGoogle ScholarPubMed
Crane, RK & Sols, A (1955) Animal tissue hexokinases. Methods in Enzymology 1, 277–286.CrossRefGoogle Scholar
Czuba, B & Vessey, DA (1981) Identification of a unique mammalian species of cholyl-CoA: amino acid N-acyltransferase. Biochimica Biophysica Acta 665, 612–614.CrossRefGoogle ScholarPubMed
Das, TK & Waterlow, JC (1974) The rate of adaptation of the urea cycle enzymes, aminotransferases and glutamic dehydrogenase to changes in dietary protein. British Journal of Nutrition 32, 353–373.CrossRefGoogle ScholarPubMed
Da Silva, AC, Fried, R & De Angelis, RC (1952) The domestic cat as a laboratory animal for experimental nutrition studies. Journal of Nutrition 46, 399–409.CrossRefGoogle ScholarPubMed
Davis, PK & Wu, G (1998) Compartmentation and kinetics of urea cycle enzymes in porcine enterocytes. Comparative Biochemistry and Physiology 119, 527–537.CrossRefGoogle ScholarPubMed
Drochner, W & Müller-Schlösser, S (1980) Digestibility and tolerance of various sugars in cats. In Nutrition of the Dog and Cats. pp. 101–111 [Anderson, RS editor] Oxford: Pergamon Press.Google Scholar
Drotman, RB & Freedland, RA (1972) Citrulline metabolism in the perfused rat liver. American Journal of Physiology 222, 973–975.CrossRefGoogle ScholarPubMed
Edmonds, MS & Baker, DL (1987) Effects of fasting on tissue amino acid concentrations and urea-cycle enzymatic activities in young pigs. Journal of Animal Science 65, 1538–1552.CrossRefGoogle ScholarPubMed
Edmonds, MS, Lowry, KR & Baker, DH (1987) Urea cycle metabolism: effects of supplemental ornithine or citrulline on performance, tissue amino acid concentrations and enzymatic activity in young pigs fed arginine-deficient diets. Journal of Animal Science 65, 706–716.CrossRefGoogle ScholarPubMed
Featherston, WR & Freedland, RA (1973) Influence of dietary protein and carbohydrate levels on liver enzyme activities in quail. Journal of Nutrition 103, 625–634.CrossRefGoogle ScholarPubMed
Featherston, WR, Rogers, QR & Freedland, RA (1973) Relative importance of kidney and liver in synthesis of arginine by the rat. American Journal of Physiology 224, 127–129.CrossRefGoogle ScholarPubMed
Freedland, RA (1964) Urea cycle adaptations in intact and adrenalectomized rats. Proceedings of the Society of Experimental Biology and Medicine 116, 692–696.CrossRefGoogle ScholarPubMed
Freytag, TL (2001) Vitamin Ametabolism and toxicity in the domestic cat. PhD Thesis, University of California, Davis.Google Scholar
Gershoff, SN, Andrus, SB, Hegsted, DM & Lentini, EA (1957) Vitamin A deficiency in cats. Laboratory Investigation 6, 227–240.Google ScholarPubMed
Hankes, LV, Henderson, LM, Brickson, WL & Elvehjem, CA (1948) Effect of amino acids on growth of rats on niacin-tryptophan deficient rations. Journal of Biological Chemistry 174, 873–881.CrossRefGoogle Scholar
Harper, AE (1965) Effect of variations in protein intake on enzymes of amino acid metabolism. In Canadian Journal of Biochemistry 43. pp 1589–1603.CrossRefGoogle ScholarPubMed
Hayes, KC, Carey, RE & Schmidt, SJ (1975) Retinal degeneration associated with taurine deficiency in the cat. Science 188, 949–951.CrossRefGoogle ScholarPubMed
Hendriks, WH, Moughan, PJ & Tarttelin, MF (1997) Urinary excretion of endogenous nitrogen metabolites in adult domestic cats using a protein-free diet and the regression technique. Journal of Nutrition 127, 623–639.CrossRefGoogle ScholarPubMed
Hickman, MA, Bruss, ML, Morris, JG & Rogers, QR (1992) Dietary protein source (soybean vs. casein) and taurine status affect kinetics of the enterohepatic circulation of taurocholic acid in cats. Journal of Nutrition 122, 1019–1028.CrossRefGoogle ScholarPubMed
Hommes, FA (1993) Inborn errors of fructose metabolism. American Journal of Clinical Nutrition 58, Suppl., 788S–795S.CrossRefGoogle ScholarPubMed
Horwitt, MK, Harvey, CC, Rothwell, WS, Cutler, JL & Haffron, D (1956) Tryptophan-niacin relationships in man. In Journal of Nutrition 60 Suppl. 1.Google Scholar
How, KL, Hazewinkel, HAW & Mol, JA (1994) Dietary dependence of cat and dog due to inadequate cutaneous synthesis of vitamin D. General Comparative Endocrinology 96, 12–18.CrossRefGoogle Scholar
Ikeda, MH, Tsuji, H, Nakamura, S, Ichiyama, A, Nishizuki, Y & Hayaishi, O (1965) Studies on the biosynthesis of nicotinamide adenine dinucleotides. II. Role of picolinic carboxylase in the biosynthesis of NAD from tryptophan in mammals. Journal of Biological Chemistry 240, 1395–1401.CrossRefGoogle ScholarPubMed
Ito, S, Wakamatsu, K & Ozeki, H (1993) Spectrophotometric assay of eumelanin in tissue samples. Analytical Biochemistry 215, 273–277.CrossRefGoogle ScholarPubMed
Johnson, WE & O'Brien, SJ (1997) Phylogenetic reconstruction of the Felidae using 16S RNA and NADH-5 mitochondrial genes. Journal of Molecular Evolution 44, Suppl. 1, S98–S116.CrossRefGoogle ScholarPubMed
Kaplan, JH & Pitot, HC (1970) Enzymatic and metabolic regulation in animals. Physiological Reviews 36, 164–254.Google Scholar
Kase, BF & Bjorkhem, I (1989) Peroxisomal bile acid-CoA: amino-acid N-acyltransferase in rat liver. Journal of Biological Chemistry 264, 9220–9223.CrossRefGoogle ScholarPubMed
Kettelhut, IC, Foss, MC & Migliorini, RH (1980) Glucose homeostasis in a carnivorous animal (cat) and in rats fed a high-protein diet. American Journal of Physiology 239, R115–R121.Google Scholar
Kienzle, E (1993 a) Carbohydrate metabolism of the cat 1. Activity of amylase in the gastrointestinal tract of the cat. Journal of Animal Physiology and Animal Nutrition 69, 92–101.CrossRefGoogle Scholar
Kienzle, E (1993 b) Carbohydrate metabolism of the cat 2. Digestion of starch. Journal of Animal Physiology and Animal Nutrition 69, 102–114.CrossRefGoogle Scholar
Koutsos, EA, Smith, S, Woods, LW & Klasing, KC (2001) Adult cockatiels (Nymphicus hollandicus) metabolically adapt to high protein diets. Journal of Nutrition 131, 2014–2020.CrossRefGoogle ScholarPubMed
Krebs, HA (1972) Some aspects of the regulation of fuel supply in omnivorous animals. Advances in Enzyme Regulation 10, 397–420.CrossRefGoogle ScholarPubMed
Leklem, JE, Woodford, J & Brown, RR (1969) Comparative tryptophan metabolism in cats and rats. Differences in adaptation of tryptophan oxygenase and in vivo metabolism of tryptophan, kynurenine and hydroxykynurenine. Comparative Biochemistry and Physiology 31, 95–109.CrossRefGoogle ScholarPubMed
MacDonald, ML, Rogers, QR & Morris, JG (1983) Role of linoleate as an essential fatty acid for the cat independent of arachidonate synthesis. Journal of Nutrition 113, 1422–1433.CrossRefGoogle ScholarPubMed
MacDonald, ML, Rogers, QR, Morris, JG & Cupps, PT (1984) Effects of linoleate and arachidonate deficiencies on reproduction and spermatogenesis in the cat. Journal of Nutrition 114, 719–726.CrossRefGoogle ScholarPubMed
McLean, JG & Monger, EA (1989) Factors determining the essential fatty acid requirements of the cat. In Nutrition of the Dog and Cat, Waltham Symposium no. 7: pp. 329–342 [Burger, IH & Rivers, JPW editors]. Cambridge: Cambridge University Press.Google Scholar
Migliorini, RH, Lindner, C, Moura, JL & Veiga, JA (1973) Gluconeogenesis in a carnivorous bird (black vulture). American Journal of Physiology 225, 1389–1392.CrossRefGoogle Scholar
Morris, JG (1999) Ineffective vitamin D synthesis in cats is reversed by an inhibitor of 7-dehydrocholosterol-Δ7-reductase. Journal of Nutrition 129, 903–908.CrossRefGoogle Scholar
Morris, JG (2001) Unique nutrient requirements of cats appear to be diet-induced evolutionary adaptations. Recent Advances in Animal Nutrition in Australia 13, 187–194.Google Scholar
Morris, JG, Earle, KE & Anderson, PA (1999) Plasma 25-hydroxyvitamin D in growing kittens is related to dietary intake of cholecalciferol. Journal of Nutrition 129, 909–912.CrossRefGoogle ScholarPubMed
Morris, JG & Rogers, QR (1978 a) Ammonia intoxication in the near-adult cat as a result of a dietary deficiency of arginine. Science 199, 431–432.CrossRefGoogle ScholarPubMed
Morris, JG & Rogers, QR (1978 b) Arginine: an essential amino acid for the cat. Journal of Nutrition 108, 1944–1953.CrossRefGoogle ScholarPubMed
Morris, JG & Rogers, QR (1982) Metabolic basis for some of the nutritional peculiarities of the cat. Journal of Small Animal Practice 23, 599–613.CrossRefGoogle Scholar
Morris, JG, Rogers, QR, Kim, SW & Backus, RC (1994) Dietary taurine requirement of cats is determined by microbial degradation of taurine in the gut. Advances in Experimental Medicine and Biology 359, 59–70.CrossRefGoogle ScholarPubMed
Morris, JG, Rogers, QR, Winterrowd, DL & Kamikawa, EM (1979) The utilization of ornithine and citrulline by the growing kitten. Journal of Nutrition 109, 724–729.CrossRefGoogle ScholarPubMed
Morris, JG, Trudell, J & Pencovic, T (1977) Carbohydrate digestion by the domestic cat (Felis catus). British Journal of Nutrition 37, 365–373.CrossRefGoogle ScholarPubMed
Morris, JG, Yu, S & Rogers, QR (2002) Red hair in black cats is reversed by addition of tyrosine to the diet. Journal of Nutrition. 132 (In the Press).CrossRefGoogle ScholarPubMed
Murphy, WJ, Sun, S, Chen, Z, Yuhki, N, Hirshmann, D, Menotti-Raymond, M & O'Brien, SJ (2000) A radiation hybrid map of the cat genome: implications of comparative mapping. Genome Research 10, 691–702.CrossRefGoogle ScholarPubMed
Myers, MR & Klasing, KC (1999) Low glucokinase activity and high rates of gluconeogenesis contribute to hyperglycemia in barn owls (Tyto alba) after a glucose challenge. Journal of Nutrition 129, 1896–1904.CrossRefGoogle ScholarPubMed
National Research Council. (1986) Nutrient Requirements of Cats. Washington DC: National Academy Press.Google Scholar
O'Brien, SJ, Menotti-Raymond, M, Murphy, WJ, Nash, WG, Weinburg, J, Stanyon, R, Copeland, NG, Jenkins, NA, Womack, JE & Marshall Graves, JA (1999) The promise of comparative genomics in mammals. Science 286, 458–481.CrossRefGoogle ScholarPubMed
O'Brien, SJ & Yuhki, N (1999) Comparative genome organization of the major histocompatibility complex: lessons from the Felidae. Immunological Reviews 167, 133–144.CrossRefGoogle ScholarPubMed
Ozeki, H, Wakamatsu, K, Ito, S & Ishguro, I (1997) Chemical characterization of eumelanins with special emphasis on 5, 6 dihydroxyindole-2-carboxylic acid content and molecular size. Analytical Chemistry 248, 149–157.Google ScholarPubMed
Park, T, Rogers, QR & Morris, JG (1999) High dietary protein and taurine increase cysteine desulfhydration in kittens. Journal of Nutrition 129, 2225–2230.CrossRefGoogle ScholarPubMed
Pawlosky, R, Barnes, A & Salem, N Jr (1994) Essential fatty acid metabolism in the feline: relationship between liver and brain production of long-chain polyunsaturated fatty acids. Journal of Lipids Research 35, 2032–2040.CrossRefGoogle ScholarPubMed
Pawlosky, RJ, Denkins, Y, Ward, G & Salem, N Jr (1997) Retinal and brain accretion of long-chain polyunsaturated fatty acids in developing felines: the effects of corn oil-based maternal diets. American Journal of Clinical Nutrition 65, 465–472.CrossRefGoogle ScholarPubMed
Pawlosky, RJ & Salem, N Jr (1996) Is dietary arachidonic acid necessary for feline reproduction?. Journal of Nutrition 126, 1081S–1085S.CrossRefGoogle ScholarPubMed
Payne, E & Laws, L (1976) The efficacy of protein supplementation in overcoming urea toxicity in sheep. British Journal of Nutrition 35, 47–54.CrossRefGoogle ScholarPubMed
Payne, E & Laws, L (1978) Tissue enzyme levels as indices of protein status in sheep. British Journal of Nutrition 39, 441–449.CrossRefGoogle ScholarPubMed
Payne, E & Morris, JG (1969) The effect of protein content of the diet on the rate of urea formation in sheep liver. Biochemical Journal 113, 659–662.CrossRefGoogle ScholarPubMed
Pecon Slattery, J & O'Brien, SJ (1998) Patterns of Y and X chromosome DNA sequences divergence during feline radiation. Genetics 148, 1245–1255.CrossRefGoogle Scholar
Pion, PD, Kittleson, MD, Rogers, QR & Morris, JG (1987) Myocardial failure in cats associated with low plasma taurine: a reversible cardiomyopathy. Science 237, 764–768.CrossRefGoogle ScholarPubMed
Quam, DD, Morris, JG & Rogers, QR (1987) Histidine requirement of kittens for growth, haematopoiesis and prevention of cataracts. British Journal of Nutrition 58, 521–532.CrossRefGoogle ScholarPubMed
Rivers, JPW, Sinclair, AJ & Crawford, MA (1975) Inability of the cat to desaturate essential fatty acids. Nature 259, 171–173.CrossRefGoogle Scholar
Rogers, QR & Morris, JG (1979) Essentiality of amino acids for the growing kitten. Journal of Nutrition 109, 718–723.CrossRefGoogle ScholarPubMed
Rogers, QR & Morris, JG (1980) Why does the cat require a high protein diet? In Nutrition of the Dog and Cat. pp. 45–66 [Anderson, RS editor] Oxford: Pergamon Press.Google Scholar
Rogers, QR, Morris, JG & Freedland, RA (1977) Lack of hepatic enzymatic adaptation to low and high levels of dietary protein in the adult cat. Enzyme 22, 348–356.CrossRefGoogle ScholarPubMed
Rogers, QR & Phang, JM (1985) Deficiency of pyrroline-5-carboxylate synthase in the intestinal mucosa of the cat. Journal of Nutrition 115, 146–150.CrossRefGoogle ScholarPubMed
Rosebrough, RW, Steele, NC & McMurtry, JP (1983) Effect of protein level and supplemental lysine on growth and urea cycle enzyme activity in the pig. Growth 47, 348–360.Google ScholarPubMed
Schimke, RT (1962) Adaptive characteristics of urea cycle enzymes in the rat. Journal of Biological Chemistry 237, 149–168.CrossRefGoogle ScholarPubMed
Schimke, RT (1963) Studies on factors affecting the levels of urea cycle enzymes in rat liver. Journal of Biological Chemistry 238, 1012–1018.CrossRefGoogle ScholarPubMed
Scott, ML (1986) Nutrition of Humans and Selected Animal Species. p. 225. New York: John Wiley and Sons.Google Scholar
Scott, PP, Graves, JP & Scott, MG (1964) Nutritional blindness in the cat. Experimental Eye Research 3, 357–364.CrossRefGoogle ScholarPubMed
Seawright, AA, English, PB & Gartner, RJW (1970) Hypervitaminosis A of the cat. Advances in Veterinary Science and Comparative Medicine 14, 1–27.Google ScholarPubMed
Sih, TR, Morris, JG & Hickman, MA (2001) Cats tolerate chronic ingestion of high levels of cholecalciferol. In American Journal of Veterinary Research 62. pp 1500–1506.CrossRefGoogle Scholar
Sinclair, AJ, McLean, JG & Monger, EA (1979) Metabolism of linoleic acid in the cat. Lipids 14, 932–936.CrossRefGoogle ScholarPubMed
Stephen, JML & Waterlow, JC (1968) Effect of malnutrition on activity of two enzymes concerned with amino acid metabolism in human liver. In Lancet. pp 118–119.CrossRefGoogle ScholarPubMed
Stipanuk, MH, Bagley, PJ, Hou, Y-C, Bella, DL, Banks, MF & Hirschberger, LL (1994) Hepatic regulation of cysteine utilization for taurine synthesis. Advances in Experimental Medicine and Biology 359, 79–89.CrossRefGoogle ScholarPubMed
Stoll, B, Burrin, DG, Henry, J, Yu, H, Jahoor, F & Reeds, PJ (1999) Substrate oxidation by the portal drained viscera of fed piglets. American Journal of Physiology 277, E168–E175.Google ScholarPubMed
Sturman, JA, Palackal, T, Lmaki, H, Moretz, RC, French, J & Wisniewski, HM (1987) Nutritional taurine deficiency and feline pregnancy and outcome. Advances in Experimental Medicine and Biology 217, 113–124.CrossRefGoogle ScholarPubMed
Sudadolnik, RJ, Stevens, CO, Dechner, RH, Henderson, LM & Hankes, LV (1957) Species variation in the metabolism of 3-hydroxyanthranilate to pyridinecarboxylic acids. Journal of Biological Chemistry 228, 973–982.CrossRefGoogle Scholar
Ureta, T (1982) The comparative isoenzymology of vertebrate hexokinases. Comparative Biochemistry and Physiology 71, 549–555.Google Scholar
Vessey, D (1978) The biochemical basis for the conjugation of bile salts with either glycine or taurine. Biochemical Journal 174, 621–626.CrossRefGoogle ScholarPubMed
Vessey, DA (1979) The co-purification and common identity of cholylCoA:glycine-and cholyl CoA:taurine-N-acyltransferase activities of bovine liver. Journal of Biological Chemistry 254, 2059–2063.CrossRefGoogle Scholar
Washizu, T, Tanaka, A, Sako, T, Washizu, M & Arai, T (1999) Comparison of the activities of enzymes related to glycolysis and gluconeogenesis in the liver of dogs and cats. Research in Veterinary Science 67, 203–204.CrossRefGoogle ScholarPubMed
Wakabayashi, Y, Henslee, JG & Jones, ME (1983) Pyrroline-5-carboxylate synthesis from glutamate by rat intestinal mucosa. Subcellular localization and temperature stability. Journal of Biological Chemistry 258, 3873–3882.CrossRefGoogle ScholarPubMed
Wakabayashi, Y & Jones, ME (1983) Pyrroline-5-carboxylate synthesis from glutamate by rat intestinal mucosa. Journal of Biological Chemistry 258, 3865–3872.CrossRefGoogle ScholarPubMed
Williams, JM, Morris, JG & Rogers, QR (1987) Phenylalanine requirement of kittens and sparing effect of tyrosine. Journal of Nutrition 117, 1102–1107.CrossRefGoogle ScholarPubMed
Windmueller, HG (1980) Enterohepatic aspects of glutamine metabolism. In Glutamine: Metabolism, Enzymology and Regulation. chapter 13: pp. 235–237 [Mora, J & Palacios, R editors]. New York: Academic Press.CrossRefGoogle Scholar
Windmueller, HG & Spaeth, AE (1974) Uptake and metabolism of plasma glutamine by the small intestine. Journal of Biological Chemistry 249, 5070–5079.CrossRefGoogle ScholarPubMed
Windmueller, HG & Spaeth, AE (1975) Intestinal metabolism of glutamine and glutamate from the lumen as compared with glutamine from blood. Archives of Biochemistry and Biophysics 171, 662–672.CrossRefGoogle ScholarPubMed
Wu, G, Davis, PK, Flynn, NE, Knabe, DA & Davidson, JT (1997) Endogenous synthesis of arginine plays an important role in maintaining arginine homeostasis in post weaning growing pigs. Journal of Nutrition 127, 2342–2349.CrossRefGoogle Scholar
Wu, G, Flynn, NE, Yan, W & Barstow, DG Jr (1995) Glutamine metabolism in chick enterocytes: absence of pyrroline-5-carboxylase synthase and citrulline synthesis. Biochemical Journal 306, 717–721.CrossRefGoogle ScholarPubMed
Wyss, A, Wirtz, G, Woggon, W, Brugger, R, Wyss, M, Friedlein, A, Bachmann, H & Hunziker, W (2000) Cloning and expression of beta, beta-carotene 15,15'-dioxygenase. Biochemistry Biophysics Research Communications 271, 334–336.CrossRefGoogle ScholarPubMed
Wyss, A, Wirtz, GM, Woggon, WD, Brugger, R, Wyss, M, Friedlein, A, Riss, G, Bachmann, H & Hunziker, W (2001) Expression pattern and localization of beta, beta-carotene 15,15'-dioxygenase in different tissues. Biochemical Journal 354, 521–529.CrossRefGoogle ScholarPubMed
Yu, S, Morris, JG & Rogers, QR (2001) Effect of low levels of dietary tyrosine on the hair colour of cats. Journal of Small Animal Practice 42, 176–180.CrossRefGoogle ScholarPubMed