Immunoreactive endothelin in plasma of nonmammalian vertebrates.
Immunoreactive endothelin (ir-ET) was estimated in plasma of nonmammalian vertebrates, using radioimmunoassay (RIA) for endothelin-1 (ET-1). Blood samples were collected from unanesthetized animals. Plasma ET was determined by RIA after extraction. Plasma levels of ir-ET were 0.7 +/- 0.2 pg/ml (n = 6) in the hagfish Eptatretus burgeri, 4.3 +/- 0.9 pg/ml (n = 5) in the banded dogfish Triakis scyllia, 3.6 +/- 0.8 pg/ml (n = 3) in the common Japanese conger Conger myriaster, 9.6 +/- 1.4 pg/ml (n = 7) in the carp Cyprinus carpio, 6.4 +/- 0.8 pg/ml (n = 5) in the bullfrog Rana catesbeiana, 6.7 +/- 0.6 pg/ml (n = 3) in the soft-shelled turtle Trionyx sinensis japonica, and 3.3 +/- 0.6 pg/ml (n = 8) in the Japanese quail Coturnix coturnix japonica. The dilution curves of the plasma extracts from each species almost paralleled the standard curve for ET-1. Analysis of the plasma extracts of the carp by reverse-phase high-performance liquid chromatography revealed that ir-ET consisted of three components, a predominant peak being located at the elution position of synthetic ET-1. The present results demonstrate clearly that an ET-1-like substance circulates in blood of nonmammalian vertebrates, suggesting an endocrine function of the peptide in these species.
Uemura
H
H
Biological Laboratory, Kanagawa Dental College, Yokosuka, Japan.
Naruse
M
M
Naruse
K
K
Hirohama
T
T
Demura
H
H
Kasuya
Y
Y
D000818:Animals; D002347:Carps / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D003370:Coturnix / Q000097:blood; D004284:Dogfish / Q000097:blood; D016232:Endothelins / Q000097:blood* / Q000276:immunology; D006196:Hagfishes / Q000097:blood; D011863:Radioimmunoassay; D011892:Rana catesbeiana / Q000097:blood; D014426:Turtles / Q000097:blood
D016232:Endothelins