Renin and Angiotensin Converting Enzyme in Elasmobranchs

Renin-like activity (RLA) and angiotensin I converting enzyme-like activity (ACELA), the two key enzymes of the renin-angiotensin system (RAS), were sought in the elasmobranch Scyliorhinus canicula. Renal extracts were desalted in a G-25 and eluted in a G-100 Sephadex column (calibration 15,000-70,000). The fractions were concentrated in a vacuum device. A 48,000-MW fraction incubated with synthetic and porcine angiotensiongen generated angiotensin I estimated by RIA. This same fraction was vasopressor in rats and dogfish. ACELA was sought in gill, heart, liver, spleen, pancreas, intestine, kidney, gonads, brain, skin, and muscle of dogfish using a spectrophotometric assay. The highest level of ACELA was found in the gills followed by spleen, kidney, and brain (33.79 +/- 2.3, 29.56 +/- 1.0, 14.62 +/- 1.0, and 13.80 +/- 2.3 nmol hippurate/min/mg protein, respectively). Intestine, gonads, skin and muscle contained no measurable amounts of ACELA. Captopril inhibited enzymatic activity from all ACELA containing tissues.