title: Bovine placental lactogen is a potent stimulator of growth and displays strong binding to hepatic receptor sites of coho salmon.
abstract: Juvenile coho salmon were treated with bovine placental lactogen (bPL) and bovine growth hormone (bGH) to examine the growth promoting activities of these proteins in a lower vertebrate. Fish were intraperitoneally injected either with 0.5 or 5.0 micrograms/g bPL or with 5.0 micrograms/g bGH once a week for 5 weeks. After only a single injection and 1 week of growth, the high dose of bPL stimulated a significant increase in weight and length relative to untreated fish or fish treated with a control protein, bovine serum albumin. At the end of the experiment, all hormone-treated groups were significantly larger than controls. Fish treated with 5 micrograms/g bPL gained more than three times as much weight as controls. The 5.0 micrograms/g bGH group grew at the same rate as fish treated with one-tenth this dose of bPL, indicating that bPL is a potent stimulator of growth in this species. Radioreceptor assays performed on coho salmon liver membrane preparations indicate that bPL binds with approximately 430-fold higher affinity than bGH, and some 8000-fold higher affinity than bovine prolactin. The action of bPL relative to the structure and function of salmonid pituitary hormones is discussed.
authors.affiliation: West Vancouver Laboratory, Fisheries and Oceans Canada, British Columbia.
authors.forename: R H
authors.initials: RH
authors.lastname: Devlin
authors.forename: J C
authors.initials: JC
authors.lastname: Byatt
authors.forename: E
authors.initials: E
authors.lastname: McLean
authors.forename: T Y
authors.initials: TY
authors.lastname: Yesaki
authors.forename: G G
authors.initials: GG
authors.lastname: Krivi
authors.forename: E G
authors.initials: EG
authors.lastname: Jaworski
authors.forename: W C
authors.initials: WC
authors.lastname: Clarke
authors.forename: E M
authors.initials: EM
authors.lastname: Donaldson
mesh_terms: D000818:Animals; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D013006:Growth Hormone / Q000494:pharmacology; D008099:Liver / Q000378:metabolism*; D008862:Microsomes, Liver / Q000378:metabolism; D017684:Oncorhynchus kisutch / Q000254:growth & development / Q000502:physiology*; D010928:Placental Lactogen / Q000494:pharmacology*; D011388:Prolactin / Q000494:pharmacology; D018000:Receptors, Peptide / Q000378:metabolism*
chemical_list: D018000:Receptors, Peptide; C028202:placental lactogen receptor; D011388:Prolactin; D013006:Growth Hormone; D010928:Placental Lactogen