Ionic and secretory response of pancreatic islet cells to minoxidil sulfate
- Laboratory of Pharmacology, Brussels Free University School of Medicine (Belgium)
Minoxidil sulfate is an antihypertensive agent belonging to the new class of vasodilators, the K+ channel openers. The present study was undertaken to characterize the effects of minoxidil sulfate on ionic and secretory events in rat pancreatic islets. The drug unexpectedly provoked a concentration-dependent decrease in 86Rb outflow. This inhibitory effect was reduced in a concentration-dependent manner by glucose and tolbutamide. Minoxidil sulfate did not affect 45Ca outflow from islets perfused in the presence of extracellular Ca++ and absence or presence of glucose. However, in islets exposed to a medium deprived of extracellular Ca++, the drug provoked a rise in 45Ca outflow. Whether in the absence or presence of extracellular Ca++, minoxidil sulfate increased the cytosolic free Ca++ concentration of islet cells. Lastly, minoxidil sulfate increased the release of insulin from glucose-stimulated pancreatic islets. These results suggest that minoxidil sulfate reduces the activity of the ATP-sensitive K+ channels and promotes an intracellular translocation of Ca++. The latter change might account for the effect of the drug on the insulin-releasing process. However, the secretory response to minoxidil sulfate could also be mediated, at least in part, by a modest Ca++ entry.
- OSTI ID:
- 5394102
- Journal Information:
- Journal of Pharmacology and Experimental Therapeutics; (United States), Journal Name: Journal of Pharmacology and Experimental Therapeutics; (United States) Vol. 258:1; ISSN 0022-3565; ISSN JPETA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Stimulus-secretion coupling of arginine-induced insulin release. Uptake of metabolized and nonmetabolized cationic amino acids by pancreatic islets
Ketone bodies and islet function: sup 45 Ca handling, insulin synthesis, and release
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
ANTIHYPERTENSIVE AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL FUNCTIONS
BODY
CALCIUM 45
CALCIUM COMPOUNDS
CALCIUM ISOTOPES
CARDIOVASCULAR AGENTS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE GLANDS
EVEN-ODD NUCLEI
GLANDS
HORMONES
INSULIN
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MEMBRANE TRANSPORT
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PANCREAS
PEPTIDE HORMONES
PROTEINS
RADIOISOTOPES
RATS
RODENTS
RUBIDIUM 86
RUBIDIUM ISOTOP
SECRETION
TRACER TECHNIQUES
VERTEBRATES