Effect of fluoride on the secretion of insulin in the rat.
Sodium fluoride (CAS 7681-49-4) 5-20 micromol/L in the extracellular space inhibited insulin secretion by isolated Langerhans islets stimulated with glucose. Insulin secretion followed a negative exponential function. This phenomenon is rapidly reversible. Perfusion of pancreatic tissue (rat) in vivo with stimulatory levels of glucose revealed that 20 micromol/L fluoride in the perfusion fluid inhibited the initial and sustained phases of insulin secretion to 15% of that of controls. The stimulatory effects of the ionophore A23187, phorbol-ester and forskolin on the secretion of insulin of isolated rat Langerhans islets in vitro were inhibited by 20 micromol/L fluoride. The results suggested that fluoride affects some stage of insulin secretion situated below the cascade of events that include the participation of calmodulin, protein-kinase C and cyclic AMP.
Menoyo
Inés
I
Laboratorio de Biología Osea, Facultad de Ciencias Médicas, Rosario, Argentina.
Rigalli
Alfredo
A
Puche
Rodolfo C
RC
D000818:Animals; D019540:Area Under Curve; D002147:Calmodulin / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D005459:Fluorides / Q000494:pharmacology*; D005947:Glucose / Q000494:pharmacology; D006706:Homeostasis / Q000187:drug effects; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism; D010179:Pancreas / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism; D010477:Perfusion; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats
D002147:Calmodulin; D007328:Insulin; D000242:Cyclic AMP; D011493:Protein Kinase C; D005947:Glucose; D005459:Fluorides