Kinetic and quantitative relationships between insulin release and WVZn efflux from perifused islets
The kinetics of zinc release and insulin secretion were compared in perifused islets previously loaded for 24 h with WVZn. In the absence of detectable insulin secretion, fractional basal WVZn release was constant at 3-5%/h throughout the experimental periods, suggesting that basal efflux of zinc is primarily from a single extragranular compartment. Glucose (25 mM) alone caused a prompt release of both WVZn and insulin. At low glucose concentrations, 3-isobutyl-1-methylxanthine (IBMX; 1 mM) did not affect either insulin or WVZn efflux; however, the combination of glucose plus IBMX caused a large and parallel biphasic release of both WVZn and insulin at ratios approximating 0.33. Similar results were obtained with glucose plus forskolin. Leucine (20 mM) plus IBMX caused a characteristic rapid secretion of insulin which waned with time. Efflux of WVZn was also prompt; however, the ratio of secreted WVZn to insulin gradually increased during stimulation from a near-theoretical value for cosecretion at the initial peak to 0.70 by the end of the stimulation. WVZn efflux was sustained even after termination of the leucine plus IBMX stimulus.
- Research Organization:
- Univ. of California, San Francisco
- OSTI ID:
- 6084480
- Journal Information:
- Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 2; ISSN ENDOA
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
ALDEHYDES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
AROMATICS
AZAARENES
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
CARBOHYDRATES
CARBOXYLIC ACIDS
COMPARTMENTS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE GLANDS
EVEN-ODD NUCLEI
GLANDS
GLUCOSE
HETEROCYCLIC COMPOUNDS
HEXOSES
HORMONES
IN VITRO
INSULIN
INTERMEDIATE MASS NUCLEI
ISOTOPES
KETO ACIDS
LEUCINE
MAMMALS
MONOSACCHARIDES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANS
PANCREAS
PEPTIDE HORMONES
PURINES
RADIOISOTOPES
RADIONUCLIDE KINETICS
RATS
RODENTS
SACCHARIDES
SECRETION
VERTEBRATES
XANTHINES
ZINC 65
ZINC COMPOUNDS
ZINC ISOTOPES