Glucose stimulates proinsulin biosynthesis by a dose-dependent recruitment of pancreatic beta cells.
Glucose is a well-known stimulus of proinsulin biosynthesis. In purified beta cells, the sugar induces a 25-fold increase in the synthesis of insulin immunoreactive material over 60-min incubation. Autoradiographic analysis of the individual cells shows that this effect is achieved via dose-dependent recruitment of pancreatic beta cells to biosynthetic activity. Recruitment of beta cells is also seen in isolated islets exposed to glucose. The sigmoidal dose-response curve for glucose-induced proinsulin biosynthesis thus reflects a heterogeneous responsiveness of pancreatic beta cells rather than a progressively increasing activity of functionally homogeneous cells. Dose-dependent recruitment of functionally diverse cells may be a ubiquitous mechanism in tissue function.
Schuit
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FC
Department of Metabolism, Vrije Universiteit Brussel, Belgium.
In't Veld
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PA
Pipeleers
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DG
D000818:Animals; D001345:Autoradiography; D002469:Cell Separation; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000494:pharmacology*; D066298:In Vitro Techniques; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D011384:Proinsulin / Q000096:biosynthesis*; D051381:Rats
D011384:Proinsulin; D005947:Glucose