Isolation and characterization of melanotropins from lamprey pituitary glands.
Three peptides containing the melanotropin-core amino-acid sequence, YXMXHFRWG, were isolated from the pituitary glands of a modern representative of the most primitive vertebrates, the sea lamprey, Petromyzon marinus. MSH-A, a nonadecapeptide (NPELYQMNHFRWGQPPTHF), is free at both ends. MSH-B, an eicosapeptide (VQESADGYRMQHFRWGQPLP), is free at the N-terminus and amidated at the C-terminus. They differ strikingly from gnathostome MSHs in structure. The third peptide, with an apparent molecular weight of 15 kDa, was tentatively designated lamprey ACTH, based on a structural feature: the N-terminal 22-residue-MSH (SVSSPKYAMGHFRWGSPDKATI) is followed by four consecutive basic amino acids (RKRR) and a ACTH-like sequence (PVRPNTSDSPEIPDYAF--). MSH-B is 10 and 100 times more potent than alpha-MSH and MSH-A, respectively, in a frog skin assay in vitro, whereas the lamprey ACTH showed no melanotropic activity. Lamprey ACTH did, however, show corticotropic activity on the lamprey pronephric and mesonephric tissue.
Takahashi
A
A
Laboratory of Molecular Endocrinology, School of Fisheries Sciences, Kitasato University, Iwate, Japan.
Amemiya
Y
Y
Nozaki
M
M
Sower
S A
SA
Joss
J
J
Gorbman
A
A
Kawauchi
H
H
D000311:Adrenal Glands / Q000187:drug effects / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000737:chemistry / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001001:Anura; D001681:Biological Assay; D002851:Chromatography, High Pressure Liquid; D007798:Lampreys; D008543:Melanins / Q000378:metabolism; D009074:Melanocyte-Stimulating Hormones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D010902:Pituitary Gland / Q000737:chemistry*; D017421:Sequence Analysis; D017385:Sequence Homology; D012867:Skin / Q000187:drug effects / Q000378:metabolism
D008543:Melanins; D010446:Peptide Fragments; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones