title: Molecular cloning and functional characterization of a prolactin-releasing peptide homolog from Xenopus laevis.
abstract: Amino acid sequences for identified prolactin (PRL)-releasing peptides (PrRPs) were conserved in mammals (>90%) or teleost fishes (100%), but there were considerable differences between these classes in the sequence (<65%) as well as in the role of PrRP. In species other than fishes and mammals, we have identified frog PrRP. The cDNA encoding Xenopus laevis prepro-PrRP, which can generate putative PrRPs, was cloned and sequenced. Sequences for the coding region showed higher identity with teleost PrRPs than mammalian homologues, but suggested the occurrence of putative PrRPs of 20 and 31 residues as in mammals. The amino acid sequence of PrRP20 was only one residue different from teleost PrRP20, but shared 70% identity with mammalian PrRP20s. In primary cultures of bullfrog (Rana catesbeiana) pituitary cells, Xenopus PrRPs increased prolactin concentrations in culture medium to 130-160% of the control, but PrRPs was much less potent than thyrotropin-releasing hormone (TRH) causing a three- to four-fold increase in prolactin concentrations. PrRP mRNA levels in the developing Xenopus brain peak in early prometamorphosis, different from prolactin levels. PrRP may not be a major prolactin-releasing factor (PRF), at least in adult frogs, as in mammals.
authors.affiliation: Ushimado Marine Laboratory, Faculty of Science, Okayama University, 130-17 Kashino, Ushimado, Setouchi 701-4303, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Aiko
authors.initials: A
authors.lastname: Oda
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Miyoko
authors.initials: M
authors.lastname: Kaneko
authors.forename: Sakae
authors.initials: S
authors.lastname: Kikuyama
authors.forename: Akio
authors.initials: A
authors.lastname: Nishikawa
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawauchi
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Tsutsui
authors.forename: Masaaki
authors.initials: M
authors.lastname: Fujimoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D007028:Hypothalamic Hormones / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D056690:Prolactin-Releasing Hormone; D014982:Xenopus laevis
chemical_list: D007028:Hypothalamic Hormones; D009479:Neuropeptides; D056690:Prolactin-Releasing Hormone