Effects of IP3, spermine, and Mg2+ on regulation of Ca2+ transport by endoplasmic reticulum and mitochondria in permeabilized pancreatic islets.
Inositol 1,4,5-trisphosphate (IP3) increased the free-Ca2+ concentration in the incubation medium of permeabilized ob/ob mouse pancreatic islets. Spermine decreased the free-Ca2+ concentration through stimulation of mitochondrial Ca2+ uptake and attenuated the effect of IP3. Mg2+ antagonized the effects of spermine, thereby increasing the free-Ca2+ concentration and enhancing the effect of IP3 on the free-Ca2+ concentration. Because IP3 releases Ca2+ from endoplasmic reticulum, these results indicate that endoplasmic reticulum and mitochondria can interact in the regulation of the free-Ca2+ concentration in the cytosol of the pancreatic beta-cell.
Lenzen
S
S
Institute of Pharmacology and Toxicology, University of Göttingen, Germany.
Rustenbeck
I
I
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002463:Cell Membrane Permeability; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D051379:Mice; D008820:Mice, Obese; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D013096:Spermine / Q000494:pharmacology*
D013096:Spermine; D015544:Inositol 1,4,5-Trisphosphate; D008274:Magnesium; D002118:Calcium