Hormone release is tied to changes in cell size in the osmoreceptive prolactin cell of a euryhaline teleost fish, the tilapia, Oreochromis mossambicus.
Prolactin (PRL) cells from a teleost fish, the tilapia, Oreochromis mossambicus, facilitate the direct study of osmoreception. The release of two prolactins, PRL(188) and PRL(177), which act in freshwater osmoregulation in teleost fish, rises in vitro within 5 min after extracellular osmolality falls. An increase in cell size accompanied this rise. Cell size and PRL release also increased, albeit more slowly, following the partial replacement of medium NaCl (55 mOsmolal) with an equivalent concentration of urea, a membrane-permeant molecule. Similar replacement using mannitol, which is membrane-impermeant, elicits no response. These findings suggest that osmoreception is linked to changes in cell volume rather than to extracellular osmolality per se.
Weber
Gregory M
GM
Hawaii Institute of Marine Biology, University of Hawaii, PO Box 1346, Coconut Island, Kaneohe, HI 96744, USA.
Seale
Andre P
AP
Richman III
N Harold
NH
Stetson
M H
MH
Hirano
Tetsuya
T
Grau
E Gordon
EG
D000818:Animals; D048429:Cell Size; D004234:Diuretics, Osmotic / Q000494:pharmacology; D006728:Hormones / Q000378:metabolism*; D008297:Male; D008353:Mannitol / Q000494:pharmacology; D009994:Osmolar Concentration; D010477:Perfusion; D010902:Pituitary Gland / Q000166:cytology* / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D012965:Sodium Chloride / Q000494:pharmacology; D017210:Tilapia / Q000378:metabolism*; D014882:Water-Electrolyte Balance / Q000502:physiology*
D004234:Diuretics, Osmotic; D006728:Hormones; D008353:Mannitol; D012965:Sodium Chloride; D011388:Prolactin