Angiotensin I-converting enzyme-like activity in tissues from the Atlantic hagfish (Myxine glutinosa) and detection of immunoreactive plasma angiotensins.
Using a highly sensitive fluorimetric assay, significant levels of angiotensin I -converting enzyme-like activity (ACELA) were detected in a range of tissues (branchial heart, gill, kidney with associated vasculature and archinephric duct, liver, whole brain and gut) from the Atlantic hagfish (Myxine glutinosa). The highest ACELA occurred in heart and gill (1.8 and 1.5 nmol His-Leu min(-1) mg protein(-1), respectively). The mammalian angiotensin I-converting enzyme (ACE) inhibitor, captopril, at 10(-5) M was a potent inhibitor of the ACELA found in all hagfish tissues. Radioimmunoassay showed that immunoreactive angiotensins (251.8+/-11.8 pM) were detectable in hagfish plasma. The validity of the assay for measurement of hagfish angiotensins was indicated by the parallelism of the angiotensin II standard curve against serially diluted hagfish plasma. Measurement of immunoreactive plasma angiotensins and detection of significant levels of ACELA in a wide range of tissues gives indirect evidence for the presence of a renin-angiotensin system in hagfishes, the earliest evolved group of craniates.
School of Biological and Chemical Sciences, Hatherly Laboratories, University of Exeter, Prince of Wales Road, Exeter EX4 4PS, UK. c.s.cobb@exeter.ac.uk
Christopher S
CS
Cobb
Susan C
SC
Frankling
Mike C
MC
Thorndyke
Frank B
FB
Jensen
J Cliff
JC
Rankin
J Anne
JA
Brown
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000809:Angiotensins / Q000097:blood* / Q000737:chemistry; D000818:Animals; D002216:Captopril / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006196:Hagfishes; D008856:Microscopy, Fluorescence; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D011863:Radioimmunoassay; D014018:Tissue Distribution
D000806:Angiotensin-Converting Enzyme Inhibitors; D000809:Angiotensins; D002216:Captopril; D007703:Peptidyl-Dipeptidase A