American journal of physiology. Endocrinology and metabolism
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Am. J. Physiol. Endocrinol. Metab. · May 2008
Inhibition of Ca2+ signaling and glucagon secretion in mouse pancreatic alpha-cells by extracellular ATP and purinergic receptors.
Glucagon secreted from pancreatic alpha-cells plays a critical role in glycemia, mainly by hepatic glucose mobilization. In diabetic patients, an impaired control of glucagon release can worsen glucose homeostasis. Despite its importance, the mechanisms that regulate its secretion are still poorly understood. ⋯ ATP-mediated inhibition of Ca2+ signaling was accompanied by a decrease in glucagon release from intact islets in contrast to the adenosine effect. Using pharmacological agonists, we found that only P2Y1 and A2A were likely involved in the inhibitory effect on Ca2+ signaling. All these findings indicate that extracellular ATP and purinergic stimulation are effective regulators of the alpha-cell function.