Norepinephrine inhibits islet lipid metabolism, sup 45 Ca sup 2+ uptake, and insulin secretion
- Universidad Complutense, Madrid (Spain)
We have previously shown that palmitate potentiates, in isolated islets, glucose-induced stimulation of insulin release, de novo lipid synthesis, and {sup 45}Ca{sup 2+} turnover in a correlative manner. Norepinephrine, a known inhibitor of the secretory response, has now been used to further investigate the relationships among the three phenomena. The amine decreased insulin secretion dose dependently in response to glucose and palmitate with alpha 2-adrenergic specificity. It also reduced similarly the oxidation of 1 mmol/l (U-{sup 14}C)palmitate as well as the incorporation of 20 mmol/l D-(U-{sup 14}C)glucose into islet phospholipids and neutral lipids through an alpha 2-adrenergic mechanism. These results indirectly suggest that alpha 2-adrenoceptor stimulation inhibits in islets both palmitate oxidation and esterification through an inactivation of long-chain acyl-CoA synthetase and other enzymes of glycerolipid synthesis. Islet uptake of {sup 45}Ca{sup 2+} was also decreased by norepinephrine with a similar sensitivity to that shown by insulin release and de novo lipid synthesis. Therefore, it is suggested that alpha 2-adrenoceptor-mediated reduction of the potentiation by palmitate of the secretory response to glucose depends on the inhibition of fatty acid metabolism and the resulting impairment of de novo lipid synthesis and {sup 45}Ca{sup 2+} turnover.
- OSTI ID:
- 7244645
- Journal Information:
- American Journal of Physiology; (USA), Vol. 257; ISSN 0002-9513
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALCIUM
MEMBRANE TRANSPORT
INSULIN
SECRETION
LIPIDS
METABOLISM
NORADRENALINE
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
CALCIUM 45
CARBON 14 COMPOUNDS
CARBON DIOXIDE
DOSE-RESPONSE RELATIONSHIPS
GLUCOSE
HEXADECANOIC ACID
IN VITRO
PHOSPHOLIPIDS
RATS
TRACER TECHNIQUES
ADRENAL HORMONES
ALDEHYDES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CALCIUM ISOTOPES
CARBOHYDRATES
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACIDS
CARDIOTONICS
CARDIOVASCULAR AGENTS
CHALCOGENIDES
DAYS LIVING RADIOISOTOPES
DRUGS
ELEMENTS
ESTERS
EVEN-ODD NUCLEI
HEXOSES
HORMONES
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
MAMMALS
METALS
MONOCARBOXYLIC ACIDS
MONOSACCHARIDES
NEUROREGULATORS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PEPTIDE HORMONES
RADIOISOTOPES
REACTION KINETICS
RODENTS
SACCHARIDES
SYMPATHOMIMETICS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques