Indexed on: 01 Dec '93Published on: 01 Dec '93Published in: General and Comparative Endocrinology
Peptides related to urotensin II have been isolated in pure form from an extract of whole brain of a teleost, the rainbow trout (Oncorhynchus mykiss) and of an elasmobranch, the longnose skate (Raja rhina). The primary structure of the trout peptide [Gly-Gly-Asn-Ser-Glu-Cys-Phe-Trp-Lys-Tyr-Cys-Val] is similar to that of urotensin II peptides isolated from the urophyses of other teleost fish. For example, trout urotensin II contains only one amino acid substitution (Thr4-->Ser) compared with urotensin II beta 1 isolated from the urophysis of the carp. The primary structure of the skate peptide [Asn-Asn-Phe-Ser-Asp-Cys-Phe-Trp-Lys-Tyr-Cys-Val] is the same as urotensin II isolated from the caudal spinal cord region of the dogfish Scyliorhinus canicula. The data provide chemical evidence to support the conclusion of earlier morphological studies [Yulis, C. R., and Lederis, K. (1988) Gen. Comp. Endocrinol. 70, 301-311) that certain species of fish possess an extensive extraurophyseal distribution of urotensin II-immunoreactive neurons.