title: Prolactin inhibits osteoclastic activity in the goldfish scale: a novel direct action of prolactin in teleosts.
abstract: In teleosts, prolactin is involved in calcium regulation, but its role in scale/bone metabolism is unclear. Using the in-vitro system with goldfish scales developed recently, we explored the effects of teleost prolactin, growth hormone, and somatolactin on osteoclasts and osteoblasts. Addition of prolactin at concentrations of 0.01-100 ng/ml reduced osteoclastic activity, partly via osteoclast apoptosis, after 6-18 h incubation. Conversely, growth hormone and somatolactin at a concentration of 100 ng/ml increased osteoclastic activity after 18 h incubation, indicating the specificity of the inhibitory effect of prolactin on osteoclastic activity. On the other hand, these three hormones promoted osteoblastic activity at concentrations of 10-100 ng/ml. The results from this study are the first demonstration of direct effects of prolactin on scale/bone metabolism and osteoclastic activity in a teleost.
authors.affiliation: Ushimado Marine Laboratory, Graduate School of Natural Science and Technology, Okayama University, Setouchi, Okayama, Japan.
authors.forename: Hideya
authors.initials: H
authors.lastname: Takahashi
authors.forename: Nobuo
authors.initials: N
authors.lastname: Suzuki
authors.forename: Chiyo
authors.initials: C
authors.lastname: Takagi
authors.forename: Mika
authors.initials: M
authors.lastname: Ikegame
authors.forename: Toshio
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Moriyama
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Hattori
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Sakamoto
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D005260:Female; D029941:Fish Proteins / Q000494:pharmacology; D006023:Glycoproteins / Q000494:pharmacology; D006054:Goldfish / Q000502:physiology*; D013006:Growth Hormone / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism; D010006:Osteoblasts / Q000187:drug effects; D010010:Osteoclasts / Q000187:drug effects*; D010907:Pituitary Hormones / Q000494:pharmacology; D011388:Prolactin / Q000494:pharmacology*; D000071681:Tartrate-Resistant Acid Phosphatase; D013997:Time Factors
chemical_list: D029941:Fish Proteins; D006023:Glycoproteins; D007527:Isoenzymes; D010907:Pituitary Hormones; C064448:somatolactin protein, fish; D011388:Prolactin; D013006:Growth Hormone; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase