Phosphatidylcholine (PC) biosynthesis in pancreatic islets of Langerhans

Conference · Fri Feb 28 23:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5454311

Hoffman, J M; Laychock, S G

Islets of Langerhans isolated from rat pancreata were incubated with (/sup 14/C)choline to determine the biosynthesis of PC by the CDP choline to determine the biosynthesis of PC by the CDPcholine pathway. Recovery of (/sup 14/C)PC in islet membranes was time-related, and stimulated by glucose (17mM) during 60 min. The rate of PC synthesis was constant during 60 min with glucose stimulation. In contrast, the sulfonylurea tolbutamide (2 mM) reduced the recovery of (/sup 14/C)choline in PC, and 8-bromo-cyclic AMP (5 mM) did not significantly affect (/sup 14/C)PC recovery. Incubation of islets in Ca/sup 2 +/-free medium enhanced glucose-stimulated recovery of (/sup 14/C)choline-labeled PC due to the inhibition of phospholipase and phospholipid hydrolysis. Inhibition of CTP:phosphocholine cytidylyltransferase with 5-deoxy-5'-isobutylthioadenosine (SIBA) reduced (/sup 14/C)PC levels and insulin release in a concentration dependent manner. Treatment with SIBA also reduced Mg/sup 2 +/-dependent Ca/sup 2 +/-ATPase activity in islet microsomes. Quantitation of membrane PC showed that glucose stimulation did not alter islet P levels. Thus, islet PC biosynthesis is linked to glucose stimulation and contributes to the maintenance of PC levels in membranes undergoing exocytosis and phospholipid hydrolysis. Adequate PC levels support Ca/sup 2 +/ pump activity and secretory mechanisms.

• Research Organization: Medical College of Virginia, Richmond
• OSTI ID: 5454311
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:3; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ALCOHOLS
ALDEHYDES
ALKALINE EARTH METALS
AMINES
AMMONIUM COMPOUNDS
AMP
ANIMALS
ATP-ASE
BIOLOGICAL PATHWAYS
BIOSYNTHESIS
BODY
CALCIUM
CARBOHYDRATES
CARBON 14 COMPOUNDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL REACTIONS
CHOLINE
DECOMPOSITION
DIGESTIVE SYSTEM
DRUGS
ELEMENTS
ENDOCRINE GLANDS
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
ESTERS
GLANDS
GLUCOSE
HEXOSES
HORMONES
HYDROLASES
HYDROLYSIS
HYDROXY COMPOUNDS
INSULIN
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPIDS
LIPOTROPIC FACTORS
LYSIS
MAMMALS
MEMBRANES
METALS
MICROSOMES
MONOSACCHARIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
ORGANS
PANCREAS
PEPTIDE HORMONES
PHOSPHOHYDROLASES
PHOSPHOLIPIDS
QUATERNARY COMPOUNDS
RATS
RODENTS
SACCHARIDES
SOLVOLYSIS
SYNTHESIS
TRACER TECHNIQUES
VERTEBRATES