title: Angiotensin converting enzyme (ACE) inhibitors and kinin metabolism: evidence that ACE inhibitors may inhibit a kininase other than ACE.
abstract: 1. Angiotensin converting enzyme (ACE) converts angiotensin I to angiotensin II, and also metabolizes bradykinin-(1-9) to bradykinin-(1-7) and bradykinin-(1-7) to bradykinin-(1-5). Increases in endogenous kinin levels may contribute to the therapeutic effects of ACE inhibitors. 2. ACE inhibitors increase vascular levels of both bradykinin-(1-9) and its ACE cleavage product bradykinin-(1-7), at doses below the threshold for ACE inhibition, leading to the proposal that ACE inhibitors may also inhibit a non-ACE kininase which cleaves both kinin peptides; this non-ACE kininase may be the major pathway of kinin metabolism in the vasculature and some other tissues. 3. In support of this proposal, ACE inhibitors potentiate bradykinin-(1-9) effects at doses which have little or no effect on ACE activity, as indicated by angiotensin I conversion to angiotensin II. ACE inhibitors also potentiate the actions of ACE-resistant kinin analogues, which may be susceptible to metabolism by a non-ACE kininase. 4. Identification and characterization of the putative non-ACE kininase which is inhibited by ACE inhibitors may reveal novel approaches to the tissue-specific modulation of kinin levels.
authors.affiliation: St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.
authors.forename: D J
authors.initials: DJ
authors.lastname: Campbell
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001920:Bradykinin / Q000378:metabolism / Q000494:pharmacology; D002216:Captopril / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007705:Kinins / Q000378:metabolism*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D007705:Kinins; D002216:Captopril; D001920:Bradykinin