Epinephrine effects on mitochondrial Krebs cycle are not mediated by typical adrenergic receptors in isolated rat hepatocytes
- Univ. of Southern California, Los Angeles (United States)
Oxidation of 2,3-{sup 14}C succinate (suc) carbons in the intra-mitochondrial Krebs cycle was used as a probe to investigate the effects of epinephrine (epi) on isolated rat hepatocytes. Hepatocytes were incubated at 30{degrees}C in Krebs-Henseleit bicarbonate buffer, pH 7.4, with 0.5 mM concentration of each of the 20 natural amino acids, 0.5 mm concentration of each of the 20 natural amino acids, 2,3-{sup 14}C suc and epi (10 uM), phenylephrine (pheni) (10uM) or isoproterenol (10 uM). Epi and phepi caused a significant increase in {sup 14}CO{sub 2} formation from 2,3-{sup 14}C suc, however, phentolamine, an {infinity}-antagonist, failed to inhibit this increased oxidation of suc carbons. Isoproterenol had no effect on hepatocyte metabolism and propranolol, a {beta}-antagonist, failed to cause any reduction in basal or epi stimulated oxidation of 2,3-{sup 14}C carbons. Unlike insulin, neither epi nor phepi had any significant effect on the anabolic utilization of suc carbons for protein or lipid synthesis. Anabolic channeling of Krebs cycle intermediates into amino acids was reduced by epi treatment of hepatocytes. Although epi treatment can enhance the oxidation of substrate through the Krebs cycle reactions, only insulin is capable of channeling these substrates into anabolic reactions. Data presented also suggest that epi effects on mitochondrial Krebs cycle oxidation are mediated through an atypical {infinity}-adrenergic receptor which is unresponsive to inhibition by non-selective {infinity}-antagonists.
- OSTI ID:
- 6056949
- Report Number(s):
- CONF-9104107--
- Journal Information:
- FASEB Journal (Federation of American Societies for Experimental Biology); (United States), Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States) Vol. 4:3; ISSN FAJOE; ISSN 0892-6638
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
ADRENALINE
AMINO ACIDS
ANIMAL CELLS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOLOGICAL EFFECTS
BIOLOGICAL PATHWAYS
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBOXYLIC ACIDS
CARDIOTONICS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
CHALCOGENIDES
DRUGS
HORMONES
INSULIN
ISOTOPE APPLICATIONS
KREBS CYCLE
LABELLED COMPOUNDS
LIPIDS
LIVER CELLS
MAMMALS
METABOLISM
MITOCHONDRIA
NEUROREGULATORS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PEPTIDE HORMONES
PROTEINS
RATS
REACTION INTERMEDIATES
RODENTS
SOMATIC CELLS
SYMPATHOMIMETICS
SYNTHESIS
TRACER TECHNIQUES
VERTEBRATES