Prolactin-releasing peptide is essential to maintain the prolactin level and osmotic balance in freshwater teleost fish.
We administered prolactin-releasing peptide (PrRP) or anti-PrRP antiserum to goldfish in fresh water and analyzed their effects on prolactin and osmoregulatory mechanisms. The pituitary mRNA level of prolactin increased by PrRP but decreased by anti-PrRP. The rate of water inflow in the gills decreased by PrRP and increased by anti-PrRP, showing that PrRP restricts branchial water permeability, as also restricted by prolactin. PrRP also expanded the mucous cell layers on the scales, which may restrict efficiently water inflow by the mucous system. Eventually, the plasma osmotic pressure decreased by anti-PrRP. We conclude that PrRP is essential to maintain prolactin levels and osmotic balance in fresh water.
Fujimoto
Masaaki
M
Department of Biological Science, Faculty of Life and Environmental Science, Shimane-University, 1060 Nishikawatsu, Matue 690-8504, Japan. fujimoto@life.shimane-u.ac.jp
Sakamoto
Tatsuya
T
Kanetoh
Tomokazu
T
Osaka
Michiyo
M
Moriyama
Shunsuke
S
D000818:Animals; D005880:Gills / Q000502:physiology; D006054:Goldfish; D006854:Hydrocortisone / Q000097:blood; D017686:Oncorhynchus mykiss; D009997:Osmotic Pressure / Q000187:drug effects; D010539:Permeability / Q000187:drug effects; D010902:Pituitary Gland / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism*; D013973:Thyrotropin-Releasing Hormone / Q000276:immunology / Q000502:physiology*
D013973:Thyrotropin-Releasing Hormone; D011388:Prolactin; D006854:Hydrocortisone