Tetrapod-type [Asp1] angiotensin is present in a holostean fish, Amia calva.
The renin-angiotensin system has been identified in various vertebrates, from elasmobranchs to mammals. Tetrapod (amphibians to mammals) angiotensin (ANG) has Asp at the N-terminus, but Asp is replaced by Asn in elasmobranch and teleost fish. ANG I has been isolated from incubates of plasma and kidney extracts of the bowfin Amia calva, a holostean fish, using the eel vasopressor activity as an assay system; its sequence was found to be H-Asp-Arg-Val-Tyr-Val-His-Pro-Phe-Asn-Leu-OH after sequence analysis, mass spectrometry, and comparison with the synthetic peptide. This sequence is identical to bullfrog ANG I. [Asn1] ANG I was not detected. Thus the bowfin is the first fish species which contains only [Asp1] ANG I. The bowfin ANG I and II were no more vasopressor than eel peptides in the bowfin, indicating that bowfin ANG II receptors do not distinguish between [Asp1] and [Asn1] peptides. In the rat, bowfin ANG I and rat [Ile5, His9] ANG I have equipressor activities when examined in different animals, but the vasopressor activity of bowfin ANG I decreased following rat ANG I in the same animals, although the activity of rat ANG I was unaffected after bowfin ANG I. The present study directly demonstrates the presence of the renin-angiotensin system in a holostean fish and showed that its ANG II receptors have not yet fully coevolved with the homologous [Asp1] peptide.
Takei
Y
Y
Ocean Research Institute, University of Tokyo, Japan. takei@ori.u-tokyo.ac.jp
Itahara
Y
Y
Butler
D G
DG
Watanabe
T X
TX
Oudit
G Y
GY
D000803:Angiotensin I / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D000811:Anguilla / Q000502:physiology; D000818:Animals; D001681:Biological Assay; D001794:Blood Pressure / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005399:Fishes / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008297:Male
D000803:Angiotensin I