Affiliation:
1. Research Service and Department of Medicine, Veterans Administration Medical Center and The University of Colorado Health Sciences Center Denver Colorado
Abstract
We investigated the effect of insulin and a hypoglycemic sulfonylurea agent glyburide on cytosolic free-Ca2+ concentrations ([Ca2+]i) in isolated ratadipocytes. Both insulin and glyburide increased [Ca2+]i in a dosedependent manner. Half-maximal effects were seen at 0.5 ng/ml of insulin and 0.5 μM glyburide. Nifedipine (25 μM), a Ca2+-channel blocker, inhibited the effectof both agents. The effect of insulin on [Ca2+]i was 40 and 70% potentiated by ambient glucose concentrations at 180 and 300 mg/dl, respectively. Depolarizingdoses of potassium (40 mM) induced an increase in cytosolic Ca2+ that was also inhibited by nifedipine. It is suggested that both insulin and glyburide increase cytosolic free Ca2+ levels at least in part by promoting Ca2+ influx through voltage-dependent Ca2+ channels.
Publisher
American Diabetes Association
Subject
Endocrinology, Diabetes and Metabolism,Internal Medicine
Cited by
50 articles.
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