Altered turnover of polyphosphoinositides in the erythrocyte membrane of the spontaneously hypertensive rat
The metabolism of inositol phospholipids of the erythrocyte membrane was compared in normotensive Wistar-Kyoto (WKY), spontaneously hypertensive (SHR), and stroke-prone SHR (SHR-SP) rats. This was performed on isolated ghost membranes by measuring the incorporation of /sup 32/P from ( gamma-/sup 32/P ) adenosine triphosphate (ATP) into the diphosphoinositides (DPI) and the triphosphoinositides (TPI) which were the only /sup 32/P-labeled phospholipids. /sup 32/P-labeling of TPI was altered in adult and 3-week-old SHR as well as in SHR-SP compared to WKY controls; the radioactivity associated with TPI in hypertensive rats was about 30% lower than that associated with TPI in age-matched normotensive controls. By contrast, the radioactivity associated with DPI was similar in both hypertensive and normotensive rats. Measurement of the phosphoinositide distribution in both SHR and WKY indicates that the change observed in /sup 32/P-TPI could not be accounted for by a reduced phosphatidylinositol content in SHR membrane. Measurement of the Mg/sup 2 +/-activated TPI-phosphomonoesterase and of the Ca/sup 2 +/-activated polyphosphoinositide phosphodiesterase activities did not show any significant difference between SHR and WKY. It thus appears that the altered phosphoinositide metabolism observed in hypertensive rats was a consequence of some alteration in the activity of kinases which are responsible for the conversion of phosphatidylinositol into DPI and TPI. These results also suggest that the defect in phosphoinositide metabolism observed in genetically hypertensive rats was not a consequence of the blood pressure elevation and could be related to the pathogenesis of hypertension.
- Research Organization:
- Hopital Necker, Paris, France
- OSTI ID:
- 5128589
- Journal Information:
- Hypertension (Dallas); (United States), Vol. 5:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PHOSPHOLIPIDS
METABOLISM
PHOSPHORUS 32
TISSUE DISTRIBUTION
ATP
CELL MEMBRANES
ERYTHROCYTES
GENETICS
HYPERTENSION
RATS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BIOLOGY
BLOOD
BLOOD CELLS
BODY FLUIDS
CARDIOVASCULAR DISEASES
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
DISEASES
DISTRIBUTION
ESTERS
ISOTOPES
LIGHT NUCLEI
LIPIDS
MAMMALS
MATERIALS
MEMBRANES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
RADIOISOTOPES
RODENTS
SYMPTOMS
VASCULAR DISEASES
VERTEBRATES
550501* - Metabolism- Tracer Techniques
550401 - Genetics- Tracer Techniques