Inhibition of neutral endopeptidase, the degradative enzyme for natriuretic peptides, in rat kidney after oral SCH 42495

Abstract

1. Inhibition of neutral endopeptidase (NEP), the degradative enzyme for atrial natriuretic peptide, was studied in vitro and in vivo using a previously characterized NEP inhibitor radioligand, 125I-labelled RB104. 2. SCH 42354, the active di-acid of the ethylester prodrug, SCH 42495, caused a concentration-dependent displacement of 125I-labelled RB104 from rat renal NEP. The concentration of SCH 42354 that displaced 50% of radioligand bound to the enzyme NEP (IC50) was 3.3 ± 0.1 nmol/l (mean ± SEM). Enalaprilat, an angiotensin converting enzyme inhibitor, did not displace 125I-labelled RB104 in concentrations up to 10 μmol/l. 3. In adult normotensive Sprague-Dawley rats, oral SCH 42495 (3-3..