INS and Impaired glucose tolerance: Thus, these findings suggest that ronacaleret rectified the impaired glucose tolerance and hypoinsulinemia of CasrNuf/+ mice by modulating their plasma calcium concentrations, and this is in keeping with our analysis of isolated Nuf mice islets, which demonstrated that Ca2+o is required for insulin release, and is also supported by a study showing that patients with chronic hypocalcemia have reduced glucose-stimulated insulin secretion (39).