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.
Laboratory of Molecular Endocrinology, School of Fisheries Sciences, Kitasato University, Iwate, Japan.
A
A
Takahashi
Y
Y
Amemiya
M
M
Nozaki
S A
SA
Sower
J
J
Joss
A
A
Gorbman
H
H
Kawauchi
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