Alteration of alpha-amylase secretion from rat parotid cells in the absence of extracellular bicarbonate.
A sufficient availability of the bicarbonate anion is required to allow a normal process of glucose-stimulated insulin release. Thus, both the removal of extracellular bicarbonate and the inhibition of carbonic anhydrase by acetazolamide suppress the insulinotropic action of glucose. In the present study, a comparable situation is documented in rat parotid cells. Thus, the absence of extracellular bicarbonate is shown to decrease by about 50% basal alpha-amylase secretion, as well as carbamylcholine- and isoproterenol-stimulated alpha-amylase output, without suppressing the enhancing action of the two agents. It is proposed, therefore, that the HCO3-anion participates in the secretory sequence at sites distal to the identification of secretagogues in both endocrine and exocrine cells.
Youssef
Rahali
R
Laboratory of Experimental Hormonology, Brussels Free University, B-1070 Brussels, Belgium.
Malaisse
Willy J
WJ
Courtois
Philippe
P
Sener
Abdullah
A
D000818:Animals; D000838:Anions; D001639:Bicarbonates / Q000378:metabolism* / Q000494:pharmacology; D002469:Cell Separation; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D007545:Isoproterenol / Q000494:pharmacology; D010306:Parotid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D000516:alpha-Amylases / Q000187:drug effects / Q000378:metabolism*
D000838:Anions; D001639:Bicarbonates; D000516:alpha-Amylases; D007545:Isoproterenol