CEACAM1 and Hyperinsulinemia: In males, the persistent increase in insulin secretion, in part mediated by the higher plasma GLP-1 secretion [13], is offset by a parallel increase in CEACAM1-mediated insulin clearance, resulting in normoinsulinemia in the young until ~9 months of age when chronic hyperinsulinemia develops largely from impaired hepatic insulin clearance that fails to counter the sustained elevation in insulin secretion [14].