Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.21 (CPT)
 4,580 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aveolar macrophages (AM) may contribute to airway inflammation via release of superoxide anion (O2-). Elevation of intracellular cyclic adenosine monophosphate (cAMP) levels has been shown to suppress O2- generation, although the exact mechanism is uncertain. To examine the inhibitory effect of cAMP against different stimuli for O2- generation, we compared the effect of cAMP on O2- generation caused by phorbol myristate acetate (PMA), a direct protein kinase C activator, and N-formyl-methionyl-leucyl-phenylalanine (FMLP), which couples its membrane receptor and stimulates guanosine triphosphate binding protein, in guinea pig AM. Cyclic nucleotide phosphodiesterase (PDE) isoenzyme inhibitors or CPT-cAMP, a cAMP analogue, were used in order to increase intracellular cAMP levels. The O2- generation caused by either PMA or FMLP was reduced by cilostazol (PDE 3 inhibitor) and Ro20-1724 (PDE 4 inhibitor), but not by zaprinast (PDE 5 inhibitor). The degree of reduction in O2- generation was not different between PMA and FMLP. Furthermore, CPT-cAMP also reduced PMA- or FMLP-induced O2- generation to a similar degree, although only high concentrations (10(-5) or 10(-4) mol/l) of this agent were effective in producing significant inhibition. A remarkable elevation of the cAMP level is required to produce the inhibitory effect on O2- generation in guinea pig AM. An elevation of cAMP may suppress O2- generation by inhibiting plural sites of the intracellular signaling pathways.
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PMID:Role of cyclic adenosine monophosphate in reducing superoxide anion generation in guinea pig alveolar macrophages. 967 Feb 6