Increased phosphoinositide breakdown by phospholipase C in erythrocyte membranes from patients with cystic fibrosis.
Phosphoinositide phospholipase C activity has been measured in erythrocyte membranes from age-matched control and CF subjects. Inositol phospholipids were labelled with [3H]myo-inositol and control experiments demonstrated that the [3H]-labelled products released by incubation of membranes with Ca2+ were derived specifically from erythrocytes (a) by purification of erythrocytes on cellulose columns, (b) by demonstration that the phospholipase C activity was inhibited by 10 mmol/l neomycin but not by 1 mmol/l p-methylsulphonylfluoride. The [3H]-labelled products were shown to be inositol phosphates by their elution from anion-exchange columns. Membranes from CF patients showed increased phospholipase C activity compared to controls which did not correlate with the degree of [3H]inositol labelling of the membranes, with pancreatic function as assessed by serum immunoreactive trypsin or with medications taken by the patients.
Doughney
C
C
Department of Medical Biochemistry, University of Wales College of Medicine, Cardiff, UK.
McPherson
M A
MA
Goodchild
M C
MC
Dormer
R L
RL
D000293:Adolescent; D000328:Adult; D002118:Calcium / Q000378:metabolism; D003550:Cystic Fibrosis / Q000097:blood* / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000201:enzymology*; D005260:Female; D006801:Humans; D008297:Male; D009355:Neomycin / Q000494:pharmacology; D010716:Phosphatidylinositols / Q000097:blood* / Q000378:metabolism; D013450:Sulfones / Q000494:pharmacology; D010738:Type C Phospholipases / Q000097:blood* / Q000378:metabolism
D010716:Phosphatidylinositols; D013450:Sulfones; C005109:methanesulfonyl fluoride; D010738:Type C Phospholipases; D009355:Neomycin; D002118:Calcium