Additive effects of glucagon and non-metabolizable analogue of leucine on glutamine catabolism in rat hepatocytes

Conference · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5018643

Zaleski, J; Erecinska, M

..beta..-2-Aminobicyclo-(2.2.1)-heptane-2-carboxylic acid (BCH), at 10 mM, a known activator of glutamate dehydrogenase, doubled the rate of urea synthesis in hepatocytes from fed rats incubated with 10 mM glutamine (gln) and 2 mM ornithine. The stimulation of urea formation was accompanied by 1.4-fold activation of /sup 14/CO/sub 2/ release from (U-/sup 14/C)gln and 2.5-fold decline in intracellular gln content. There was no significant change in glutamate level while 2-oxoglutarate and malate increased by 1.3- and 2.4-fold, respectively. In hepatocytes from fasted rats BCH was similarly effective in stimulation of urea and /sup 14/CO/sub 2/ formation and it also doubled the rate of glucose synthesis. Effects of BCH on hepatocytes from fasted rats were associated with about 2-fold elevation of glutamate, aspartate and alanine levels. The effects of BCH and glucagon (a putative glutaminase activator) on urea, /sup 14/CO/sub 2/ and glucose formation were additive. The results suggest that BCH-induced activation of gln catabolism in hepatocytes is caused primarily by stimulation of glutaminase rather than glutamate dehydrogenase. It seems that the mechanisms of activation of glutaminase by BCH and glucagon are different.

• Research Organization: Univ. of Pennsylvania Medical School, Philadelphia
• OSTI ID: 5018643
• Report Number(s): CONF-8606151-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:6; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
AMIDASES
AMIDES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BIOLOGICAL EFFECTS
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBOXYLIC ACIDS
CATABOLISM
CHALCOGENIDES
CHEMICAL ACTIVATION
ENZYMES
FASTING
GLUCAGON
GLUCOSE
GLUTAMINE
HEXOSES
HORMONES
HYDROLASES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LEUCINE
LIVER CELLS
MAMMALS
METABOLISM
MONOSACCHARIDES
NON-PEPTIDE C-N HYDROLASES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORNITHINE
OXIDES
OXYGEN COMPOUNDS
PEPTIDE HORMONES
PEPTIDES
POLYPEPTIDES
PROTEINS
RATS
RODENTS
SACCHARIDES
SOMATIC CELLS
TRACER TECHNIQUES
VERTEBRATES