Cell swelling induced secretion of TRH by posterior pituitary, hypothalamic paraventricular nucleus and pancreatic islets: effect of L-canavanine

The aims of this study were to test if ethanol induces thyrotropin-releasing hormone (TRH) secretion in vitro from the posterior pituitary and hypothalamic explants by a mechanism involving cell swelling, and to characterize the pathway of stimulated secretion. Ethanol, at a concentration of 80 mM,...

Full description

Saved in:
Bibliographic Details
Published in:Cellular and molecular neurobiology 2002-02, Vol.22 (1), p.35-46
Main Authors: Najvirtová, M, Baqi, L, Kucerová, J, Strbák, V
Format: Article
Language:English
Subjects:
Animals
Canavanine - pharmacology
Cell Size - drug effects
Cell Size - physiology
Ethanol - pharmacology
In Vitro Techniques
Islets of Langerhans - cytology
Islets of Langerhans - drug effects
Islets of Langerhans - metabolism
Male
Paraventricular Hypothalamic Nucleus - cytology
Paraventricular Hypothalamic Nucleus - drug effects
Paraventricular Hypothalamic Nucleus - metabolism
Potassium - pharmacology
Rats
Rats, Wistar
Thyrotropin-Releasing Hormone - metabolism
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The aims of this study were to test if ethanol induces thyrotropin-releasing hormone (TRH) secretion in vitro from the posterior pituitary and hypothalamic explants by a mechanism involving cell swelling, and to characterize the pathway of stimulated secretion. Ethanol, at a concentration of 80 mM, stimulated the release of TRH from the posterior pituitary, the hypothalamic paraventricular nucleus, the median eminence, and the brain septum, when administered only in isosmolar but not in hyperosmolar medium. This indicates the involvement of a cell swelling-inducing mechanism. L-canavanine in a concentration of 3 mM, increased the basal and hyposmosis-induced TRH secretion from the posterior pituitary and the paraventricular nucleus, and both basal and ethanol-induced TRH secretion from isolated pancreatic islets. This indicates the presence of both constitutive and regulatory secretory pathways. Our results suggest that cell swelling induces exocytosis from clathrin coated granules.
ISSN:0272-4340
DOI:10.1023/A:1015389628096