Analysis of regulatory factors for urea synthesis by isolated perfused rat liver. I. Urea synthesis with ammonia and glutamine as nitrogen sources.

Analysis of regulatory factors for urea synthesis by isolated perfused rat liver. I. Urea synthesis with ammonia and glutamine as nitrogen sources. Research Abstract Details 

Research Abstract Table of Contents

Jump to the:

Analysis of regulatory factors for urea synthesis by isolated perfused rat liver. I. Urea synthesis with ammonia and glutamine as nitrogen sources. Abstract Text:

T Saheki,N Katunuma,

Urea synthesis was studied using the isolated liver perfusion with ammonium cholride and glutamine as nitrogen sources. The rate of urea formation increases with ammonium cholorde concentration up to 5mM, and the rate remained constant in the range between 5 and 20mM of ammonium chloride as the substrate. The concentration of ammonia in the medium to support the half-maximum velocity of urea formation was 0.7mM. The rate of urea formation was stimulated by the addition of 2.5mM ornithine, and the greater part of the ornithine which was taken up into the liver was accumulated as citrulline in the presence of ammonia. A considerable accelerating effect of N-acetylglutamate on the synthetic rate was observed, but a rather high concentration of N-acetylglutamate was required in order to obtain the maximum effect possibly, because its permeability into liver cells may be limited. A marked additive effect on the rate of urea formation was observed with the combined addition of ornithine and N-acetylglutamate. The metabolic conversion of glutamine nitrogen to urea in the perfused rat liver and the effect of several compounds which stimulated urea synthesis with ammonia were further examined. The process of conversion of glutamine nitrogen to urea might be composed of the following three steps. In the first lag phase, a small amount of glutamine was removed from the medium. In the second stage, the glutamine level decreased rapidly and ammonia was accumulated in the perfusate. The third stage was a period in which glutamine concentration remained at a constant low level, and the accumulated ammonia was rapidly conversed to urea. The rate of urea formation in this third stage was found to be much higher than that with ammonia as the substrate. The maximum rate of glutamine removal was obtained at pH 7.7 of the perfusate and at a concentration of 10mM glutamine. Urea formation with glutamine was also stimulated by the addition of ornithine, malate, or N-acetylglutamate, which had accelerating effects on the urea synthesis with ammonia. This stimulation was due to an effective conversion of ammonia to urea, but no change in the rate of removal glutamine was obtained.

Analysis of regulatory factors for urea synthesis by isolated perfused rat liver. I. Urea synthesis with ammonia and glutamine as nitrogen sources. Publishing Authors By Initials

T Saheki,N Katunuma,

For similar organic chemicals: urea research abstracts see: organic chemicals: urea research

PUBMED ID PMID:

MEDLINE DATE:

Analysis of regulatory factors for urea synthesis by isolated perfused rat liver. I. Urea synthesis with ammonia and glutamine as nitrogen sources. Journal Published:

PUBLICATION TYPE: Journal Article

Journal: Journal of biochemistry

VOLUME: 77

Page Numbers: 659-69

Journal Abbreviation: J. Biochem.

ISSN: 0021-924X

DAY: 19

MONTH: Mar

YEAR: 1975

Analysis of regulatory factors for urea synthesis by isolated perfused rat liver. I. Urea synthesis with ammonia and glutamine as nitrogen sources. Information

Number of References:

LANGUAGE: eng

NlmUniqueID: 376600

Analysis of regulatory factors for urea synthesis by isolated perfused rat liver. I. Urea synthesis with ammonia and glutamine as nitrogen sources. Keywords Mesh Terms:

KEYWORDS: Urea

MESH TERMS: biosynthesis

Chemical & Substance for Abstract: Analysis of regulatory factors for urea synthesis by isolated perfused rat liver. I. Urea synthesis with ammonia and glutamine as nitrogen sources. Information

Substance Name: Nitrogen

Registry Number: 7727-37-9

Grant and Affiliation Information for Analysis of regulatory factors for urea synthesis by isolated perfused rat liver. I. Urea synthesis with ammonia and glutamine as nitrogen sources.

AFFILIATION:

Country: JAPAN

AGENCY:

GRANT:

ACRONYM:

MEDLINETA: J Biochem

REFSOURCE:

DATABASENAME:

ACCESSION NUMBER:

Number Hits: 0

Analysis of regulatory factors for urea synthesis by isolated perfused rat liver I Urea synthesis with ammonia and glutamine as nitrogen sources Related Publications

• Analysis of regulatory factors for urea synthesis by isolated perfused rat liver. I. Urea synthesis with ammonia and glutamine as nitrogen sources.
• Analysis of regulatory factors for urea synthesis by isolated perfused rat liver. II. Comparison of urea synthesis in livers of rats subjected to different dietary conditions.
• Comparative studies on glutamine, serine, and glycine metabolisms in ureotelic and uricotelic animals.
• Comparison of properties and inducibility of glutamate dehydrogenases in rat kidney and liver.
• Connectin, an elastic protein of muscle. Effects of proteolytic enzymes in situ.
• Crystallization and properties of human liver ornithine aminotransferase.
• Effect of a serine protease on isolated myofibrils.
• Effect of ammonia on tricarboxylate utilization in rat liver mitochondria.
• Effects of estrogen on the turnover rates of ornithine amino transferase in rat liver and kidney.
• Immunological cross-reactivity of gamma-glutamyltranspeptidases from human and rat kidney, liver, and bile.
• Immunological studies on cathepsins B and H from rat liver.
• Inhibitions by E-64 derivatives of rat liver cathepsin B and cathepsin L in vitro and in vivo.
• Inhibitions of cathepsin B and cathepsin L by E-64 in vivo. II. Incorporation of [3H]E-64 into rat liver lysosomes in vivo.
• Mode of inhibition of ornithine aminotransferase by L-canaline.
• Proceedings: Regulation of intracellular enzyme degradation in various mammalian tissues.
• Purification and characterization of yeast protease B.
• Purification and comparison of glutamine synthetase from rat and chick livers.
• Purification and properties of a new cathepsin from rat liver.
• Selective cleavage of peptide bonds by a serine protease from rat skeletal muscle.
• Selective cleavage of peptide bonds by a serine protease from the muscle layer of rat small intestine.
• Selective cleavage of peptide bonds by cathepsins L and B from rat liver.
• Serine protease in mice with hereditary muscular dystrophy.
• Studies on the structure of gamma-glutamyltranspeptidase. I. Correlation between sialylation and isozymic forms.
• Studies on the structure of gamma-glutamyltranspeptidase. II. Location of the segment anchoring gamma-glutamyltranspeptidase to the membrane.
• Studies on the structure of rat liver ornithine aminotransferase.
• Studies on the turnover rates of ornithine aminotransferase in Morris hepatoma 44 and host liver.
• Susceptibilities of various myofibrillar proteins to cathepsin B and morphological alteration of isolated myofibrils by this enzyme.
• Susceptibilities of various myofibrillar proteins to muscle serine protease.
• The serine protease from rat liver and hepatoma 8999. Location and role in mitochondrial protein degradation.
• Use of rabbit antibody IgG-loaded silicone pieces for the sandwich enzymoimmunoassay of macromolecular antigens.