Different signaling pathways involved in glucose- and cell swelling-induced insulin secretion by rat pancreatic islets in vitro
| Autor: | Zuzana, Bacová, Július, Benický, Elena E, Lukyanetz, Igor A, Lukyanetz, Vladimir, Strbák |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Male
Indoles In Vitro Techniques Rats Enzyme Activation Maleimides Islets of Langerhans Norepinephrine Glucose Hypotonic Solutions Insulin Secretion Animals Insulin Calcium Enzyme Inhibitors Rats Wistar Egtazic Acid Phorbol 12 13-Dibutyrate Protein Kinase C Cell Size Chelating Agents Signal Transduction |
| Zdroj: | Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology. 16(1-3) |
| ISSN: | 1015-8987 |
| Popis: | The objective was to compare signal transduction pathways exploited by glucose and cell swelling in stimulating insulin secretion.Isolated rat (Wistar) pancreatic islets were stimulated in vitro by 20 mmol/l glucose or 30% hypotonic medium (202 mOsm/kg) in various experimental conditions.Glucose did not stimulate insulin release in calcium free medium. Cell swelling-induced insulin release in calcium free medium, even in the presence of the membrane permeable calcium chelator BAPTA/AM (10 micromol/l). Protein kinase C (PKC) inhibitor bisindolylmaleimide VIII (1 micromol/l) abolished the stimulation of insulin secretion by glucose but did not affect the swelling-induced insulin release. PKC activator phorbol 12-13-dibutyrate (1 micromol/l) stimulated insulin secretion in medium containing Ca2+ and did not potentiate insulin secretion stimulated by hypotonic extracellular fluid. Dilution of the medium (10-30%) had an additive effect on the glucose-induced insulin secretion. Noradrenaline (1 micromol/l) abolished glucose-induced insulin secretion but did not inhibit hypotonic stimulation either in presence or absence of Ca2+.Glucose- and swelling-induce insulin secretion through separate signal transduction pathways. Hyposmotic stimulation is independent from both the extracellular and intracellular Ca2+, does not involve PKC activation, and could not be inhibited by noradrenaline. These data indicate a novel signaling pathway for stimulation of insulin secretion exploited by cell swelling. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|