Characterization of rat heart alkaline phosphatase isoenzymes and modulation of activity
Braz. j. med. biol. res
;
41(7): 600-609, July 2008. ilus, graf
Article
in English
| LILACS
| ID: lil-489518
ABSTRACT
Alkaline phosphatase (ALP) is important in calcification and its expression seems to be associated with the inflammatory process. We investigated the in vitro acute effects of compounds used for the prevention or treatment of cardiovascular diseases on total ALP activity from male Wistar rat heart homogenate. ALP activity was determined by quantifying, at 410 nm, the p-nitrophenol released from p-nitrophenylphosphate (substrate in Tris buffer, pH 10.4). Using specific inhibitors of ALP activity and the reverse transcription-polymerase chain reaction, we showed that the rat heart had high ALP activity (31.73 ± 3.43 nmol p-nitrophenol·mg protein-1·min-1) mainly tissue-nonspecific ALP but also tissue-specific intestinal ALP type II. Both ALP isoenzymes presented myocardial localization (striated pattern) by immunofluorescence. ALP was inhibited a) strongly by 0.5 mM levamisole, 2 mM theophylline and 2 mM aspirin (91, 77 and 84 percent, respectively) and b) less strongly by 2 mM L-phenylalanine, 100 mL polyphenol-rich beverages and 0.5 mM progesterone (24, 21 to 29 and 11 percent, respectively). â-estradiol and caffeine (0.5 and 2 mM) had no effect; 0.5 mM simvastatin and 2 mM atenolol activated ALP (32 and 36 percent, respectively). Propranolol (2 mM) tended to activate ALP activity and corticosterone activated (18 percent) and inhibited (13 percent) (0.5 and 2 mM, respectively). We report, for the first time, that the rat heart expresses intestinal ALP type II and has high total ALP activity. ALP activity was inhibited by compounds used in the prevention of cardiovascular pathology. ALP manipulation in vivo may constitute an additional target for intervention in cardiovascular diseases.
Full text:
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Index:
LILACS (Americas)
Main subject:
Alkaline Phosphatase
/
Enzyme Inhibitors
/
Myocardium
Limits:
Animals
Language:
English
Journal:
Braz. j. med. biol. res
Journal subject:
Biology
/
Medicine
Year:
2008
Type:
Article
Affiliation country:
Portugal
Institution/Affiliation country:
Universidade do Porto/PT
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