Effects of inhibition of mitochondrial ATP synthesis on phosphoinositide metabolism in rabbit aorta
The authors tested a hypothesis that the plasma membrane phosphoinositide kinase reactions are sensitive to decreases in mitochondrial energy delivery. This hypothesis followed the finding of Lundberg et al of a high Km for ATP for PI and PIP kinase. In aortic rings contracted with norepinephrine (NE), hypoxia causes a decrease in J/sub ATP/ from 2.2 to 1.6 ..mu..mole/(min)(gram wet wt), and a decrease in PCr/total Cr from 0.68 to 0.23, without a detectable change in (ATP). Rings were incubated with (/sup 3/H)-myo-inositol for 30 min at 37/sup 0/C which labelled myo-inositol with only a small /sup 3/H incorporation into inositol phospholipids. Rings were then activated with 18 ..mu..M NE, either during normoxia or hypoxia. The authors measured specific activities of inositol phospholipids and myo-inositol. Hypoxia caused a decrease in the NE-activated inositol phospholipid flux rate from 0.052 +/- 0.006 to 0.023 +/- 0.004 nmoles/(min)(100 nmoles PL Pi), a decrease in the rate of increase in PI, PIP and PIP/sub 2/ specific activities, a decrease in the rate of increase in IP, IP/sub 2/, IP/sub 3/ and IP/sub 4/ radioactivities, and an increase in PIP pool size (and the ratio PIP/PIP/sub 2/). The authors conclude: inositol phospholipid metabolism is sensitive to decreases in delivery of energy to plasma membrane PIP kinase and ATP-dependent reactions involved in PI resynthesis.
- Research Organization:
- Univ. of Pennsylvania, Philadelphia
- OSTI ID:
- 6023853
- Report Number(s):
- CONF-870644-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 46:6; ISSN FEPRA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
ANOXIA
AORTA
ARTERIES
ATP
BIOSYNTHESIS
BLOOD VESSELS
BODY
CARBOHYDRATES
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CELL MEMBRANES
ENZYMES
ESTERS
INHIBITION
INOSITOL
INOSITOLS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPIDS
MAMMALS
MEMBRANES
METABOLISM
MITOCHONDRIA
MONOSACCHARIDES
MUSCLES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
ORGANS
PHOSPHOLIPIDS
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
RABBITS
SACCHARIDES
SYNTHESIS
TRACER TECHNIQUES
TRANSFERASES
TRITIUM COMPOUNDS
VERTEBRATES