Bovine placental lactogen is a potent stimulator of growth and displays strong binding to hepatic receptor sites of coho salmon.
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.
Devlin
R H
RH
West Vancouver Laboratory, Fisheries and Oceans Canada, British Columbia.
Byatt
J C
JC
McLean
E
E
Yesaki
T Y
TY
Krivi
G G
GG
Jaworski
E G
EG
Clarke
W C
WC
Donaldson
E M
EM
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*
D018000:Receptors, Peptide; C028202:placental lactogen receptor; D011388:Prolactin; D013006:Growth Hormone; D010928:Placental Lactogen