Teleost-type angiotensin is present in Australian lungfish, Neoceratodus forsteri.
Angiotensin I (ANG I) was produced from the incubation of lungfish plasma with homologous kidney extracts. The purified peptide was found to have the sequence of H-Asn-Arg-Val-Tyr-Val-His-Pro-Phe-Thr-Leu-OH, which is homologous for the first eight residues with all teleost angiotensins so far sequenced, although lungfish generally possess tetrapod-type hormones. The lungfish decapeptide (ANG I) induced dose-dependent increases in arterial pressure in the rat. The lungfish octapeptide (ANG II) released aldosterone from kidney-adrenal tissue in vitro in a dose-dependent manner and induced dose-dependent increases in arterial pressure of the lungfish. Substitution of asparagine with aspartic acid in the first position (tetrapod-type ANG II) did not alter the blood pressure response significantly, but a second substitution of the valine in the (5)-position with isoleucine (ANG II form found in human and rat) abolished the rise in arterial pressure in lungfish over the same dose range.
Joss
J M
JM
School of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
Itahara
Y
Y
Watanabe
T X
TX
Nakajima
K
K
Takei
Y
Y
D000803:Angiotensin I / Q000032:analysis*; D000811:Anguilla; D000818:Animals; D001315:Australia; D001681:Biological Assay; D005075:Biological Evolution; D005399:Fishes / Q000378:metabolism*; D006801:Humans; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012084:Renin-Angiotensin System / Q000502:physiology*; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
D000803:Angiotensin I