CEACAM1 and Insulin resistance: Consistent with the key role for CEACAM1 in diet-induced insulin resistance and hepatosteatosis, adenoviral-mediated redelivery of wild-type, but not phosphorylation-defective CEACAM1 to the liver, completely reverses these metabolic abnormalities even while maintaining mice on a high-fat diet (27), demonstrating a causative role for the decrease in hepatic CEACAM1 level in sustaining diet-induced systemic insulin resistance and hepatic steatosis.