Source of /sup 3/H-labeled inositol bis- and monophosphates in agonist-activated rat parotid acinar cells

Journal Article · Mon Jun 05 04:00:00 EDT 1989 · J. Biol. Chem.; (United States)

OSTI ID:5767919

Hughes, A R; Putney, Jr, J W

The kinetics of (3H)inositol phosphate metabolism in agonist-activated rat parotid acinar cells were characterized in order to determine the sources of (3H)inositol monophosphates and (3H)inositol bisphosphates. The turnover rates of D-myo-inositol 1,4,5-trisphosphate and its metabolites, D-myo-inositol 1,4-bisphosphate and D-myo-inositol 1,3,4-trisphosphate, were examined following the addition of the muscarinic receptor antagonist, atropine, to cholinergically stimulated parotid cells. D-myo-Inositol 1,4,5-trisphosphate declined with a t1/2 of 7.6 +/- 0.7 s, D-myo-inositol 1,3,4-trisphosphate declined with a t1/2 of 8.6 +/- 1.2 min, and D-myo-inositol 1,4-bisphosphate was metabolized with a t1/2 of 6.0 +/- 0.7 min. The sum of the rates of flux through D-myo-inositol 1,4-bisphosphate and D-myo-inositol 1,3,4-trisphosphate (2.54% phosphatidylinositol/min) did not exceed the calculated rate of breakdown of D-myo-inositol 1,4,5-trisphosphate (2.76% phosphatidylinositol/min). Thus, there is no evidence for the direct hydrolysis of phosphatidylinositol 4-phosphate in intact cells since D-myo-inositol 1,4-bisphosphate formation can be attributed to the dephosphorylation of D-myo-inositol 1,4,5-trisphosphate. The source of the (3H)inositol monophosphates also was examined in cholinergically stimulated parotid cells. When parotid cells were stimulated with methacholine, D-myo-inositol 1,4,5-trisphosphate, D-myo-inositol 1,3,4,5-tetrakisphosphate, D-myo-inositol 1,4-bisphosphate, and D-myo-inositol 4-monophosphate levels increased within 2 s, whereas D-myo-inositol 1-monophosphate accumulation was delayed by several seconds. Rates of (3H)inositol monophosphate accumulation also were examined by the addition of LiCl to cells stimulated to steady state levels of (3H)inositol phosphates.

• Research Organization: National Institute of Environmental Health Sciences, Research Triangle Park, NC (USA)
• OSTI ID: 5767919
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 264:16; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALOIDS
ANIMALS
ATROPINE
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOCHEMICAL REACTION KINETICS
BIOCHEMISTRY
BODY
CHEMICAL REACTIONS
CHEMISTRY
CHROMATOGRAPHY
DRUGS
ESTERS
GLANDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LIPIDS
LIQUID COLUMN CHROMATOGRAPHY
MAMMALS
METABOLISM
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANS
PARASYMPATHOLYTICS
PHOSPHOLIPIDS
PHOSPHORYLATION
RATS
REACTION KINETICS
RODENTS
SALIVARY GLANDS
SEPARATION PROCESSES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES