Mathematical modelling of stimulus-secretion coupling in the pancreatic B-cell. V. Threshold phenomenon for the response to cyclic AMP.
Recent experimental data suggest that a rise in cyclic AMP content of pancreatic islet cells may have little effect upon cytosolic Ca2+ activity. Hence, a mathematical model for stimulus-secretion coupling was designed in which cyclic AMP fails to affect Ca2+ movements in the islet cells, but augments the responsiveness to cytosolic Ca2+ of the effector system for insulin release. Provided that the latter effect of cyclic AMP becomes operative only when the nucleotide concentration exceeds a critical threshold value, the mathematical model was found suitable to predict the dynamics of both insulin release and 45Ca fluxes in islets deprived of or exposed to D-glucose, Ca2+ and a phosphodiesterase inhibitor.
Owen
A
A
Laboratory of Experimental Medicine, Brussels Free University, Belgium.
Malaisse
W J
WJ
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002122:Calcium Chloride / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D008433:Mathematics; D008954:Models, Biological; D013806:Theophylline / Q000494:pharmacology
D007328:Insulin; D004533:Egtazic Acid; D013806:Theophylline; D000242:Cyclic AMP; D005947:Glucose; D002122:Calcium Chloride; D002118:Calcium