PMID: 8593933Mar 1, 1996Paper

cAMP-signaling pathway acts in selective synergism with glucose or tolbutamide to increase cytosolic Ca2+ in rat pancreatic beta-cells

Diabetes
K YaekuraT Yada

Abstract

cAMP and the insulinotropic peptides that raise cAMP glucose-dependently increase the cytosolic free Ca2+ concentration ([Ca2+]i) in pancreatic beta-cells, which is tightly linked to the potentiation of glucose-induced insulin release. We examined whether cAMP increases [Ca2+]i in specific cooperation only with glucose or also with other insulin secretagogues that act through different mechanisms. [Ca2+]i in single rat pancreatic beta-cells was measured by dual-wavelength fura-2 microfluorometry. In the presence of a stimulatory concentration of glucose (8.3 mmol/l) and the moderate elevation in [Ca2+]i induced by it, forskolin, an activator of adenylyl cyclase, or dibutyryl cAMP produced a marked additional increase in [Ca2+]i but was ineffective at the basal 2.8 mmol/l glucose. These cAMP-elevating agents also potentiated the effect of tolbutamide on [Ca2+]i. The cAMP-induced increase in [Ca2+]i was completely and selectively inhibited by a blocker of cAMP-dependent protein kinase A (PKA), and by nitrendipine, a blocker of the L-type Ca2+ channel. However, in the presence of high KCl and the [Ca2+]i elevation induced by it, a rise in cAMP failed to further increase [Ca2+]i, whereas BAY K8644, an agonist of L-type Ca2+ channel...Continue Reading

Citations

Feb 7, 1998·Proceedings of the National Academy of Sciences of the United States of America·L B LesterJ D Scott
Jan 20, 1999·Proceedings of the National Academy of Sciences of the United States of America·N TakahashiH Kasai
Apr 22, 2010·Journal of Diabetes Investigation·Yutaka SeinoDaisuke Yabe
Nov 15, 2005·The Journal of Physiology·Hiroyasu HatakeyamaNoriko Takahashi
Aug 9, 2011·Progress in Biophysics and Molecular Biology·Daisuke Yabe, Yutaka Seino
Mar 10, 2009·Journal of Cellular and Molecular Medicine·Tomie MuraokaToshihiko Ishida
Dec 2, 2004·Canadian Journal of Physiology and Pharmacology·John Turk, Sasanka Ramanadham
Jan 1, 1997·Critical Reviews in Biochemistry and Molecular Biology·P A Bullock
Mar 8, 2002·American Journal of Physiology. Endocrinology and Metabolism·Zhongmin MaSasanka Ramanadham

❮ Previous
Next ❯

Related Concepts

Related Feeds

American Diabetes Association Journals

Discover the latest diabetes research published by the journals from the American Diabetes Association.

Calcium & Bioenergetics

Bioenergetic processes, including cellular respiration and photosynthesis, concern the transformation of energy by cells. Here is the latest research on the role of calcium in bioenergetics.