Regulation and specificity of glucose-stimulated insulin gene expression in human islets of Langerhans.

The insulin response of cultured human islets of Langerhans was measured at both mRNA and polypeptide levels in response to natural and pharmacological stimuli. We report a dosage dependent stimulation of both mRNA levels and insulin secretion by extracellular glucose, and present evidence that islet responsiveness can be divided into two temporal phases: an early response, apparently under post-transcriptional control, and a late phase in which insulin messenger accumulates. Although glucose effects in man are similar to rodents, there are important differences, especially with respect to modulation of glucose stimulation by activators of beta-cell protein kinases.