title: Cell volume induced hormone secretion: studies on signal transduction and specificity.
abstract: Cell swelling causes an immediate secretory response in various cell types. Induced secretion possesses some unique features suggesting the involvement of a specific signal transduction pathway. The effect of 10-20 microM GdCl3, 100 microM HgCl2, 1-100 microM indomethacin and 1-20 microM nordihydroguaiaretic acid (NDGA) on cell swelling-induced hormone secretion (isosmotic 80 mM ethanol or 15-30% hyposmotic medium) from incubated rat hypothalamic paraventricular nucleus (PVN) and posterior pituitary (oxytocin and TRH), isolated pancreatic islets (TRH) and perifused anterior pituitary cells (prolactin) were examined. To determine how general the effect of cell swelling is on exocytotic secretion, the release of two different neurohormones (thyrotropin releasing hormone -TRH and oxytocin) from the same tissue explant were studied. Both hyposmotic medium or isosmotic ethanol containing medium induced immediate TRH and prolactin release from the tested tissues. The effect of GdCl3, HgCl2, NDGA or indomethacin showed no inhibition of cell swelling induced secretion. In contrast to TRH, oxytocin release was not induced by isosmotic ethanol containing medium from the PVN or posterior pituitary.
  
  
  CONCLUSIONS
  These data indicate that signal transduction leading to exocytosis after cell swelling does not involve GdCl3 sensitive stretch activated channels, mercury sensitive aquaporins, or indomethacin and NDGA sensitive mediators including prostaglandins and leukotriens. Cell swelling-induced exocytosis possesses limited selectivity; cells specifically involved in water and salt regulation retain their specific response to osmotic stimuli.
authors.affiliation: Department of Medicine, Oregon Health Sciences University, Portland, Oregon, USA.
authors.forename: Miroslava
authors.initials: M
authors.lastname: Najvirtová
authors.forename: Susan E
authors.initials: SE
authors.lastname: Greer
authors.forename: Monte A
authors.initials: MA
authors.lastname: Greer
authors.forename: Lahim
authors.initials: L
authors.lastname: Baqi
authors.forename: Július
authors.initials: J
authors.lastname: Benický
authors.forename: Vladimír
authors.initials: V
authors.lastname: Strbák
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D048429:Cell Size; D006728:Hormones / Q000378:metabolism*; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009995:Osmosis / Q000187:drug effects; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010904:Pituitary Gland, Posterior / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012680:Sensitivity and Specificity; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D006728:Hormones; D016718:Arachidonic Acid