2015 ACVIM Forum Research Abstract Program

Our hypothesis was supported and we conclude that OST results have acceptable repeatability. Incretin hormone concentrations were not as strongly correlated between test days as resting HMW adiponectin concentrations. Cortisol binding globulin (CBG) binds circulating cortisol in plasma, and regulates the amount of free cortisol available in circulation by influencing metabolic clearance rate. Free cortisol is the only form that is able to enter cells to bind cytosolic cortisol receptors, and thus has long been presumed to be the biologically active form of cortisol. However, recent research in rodents and humans suggests CBG-bound cortisol may interact with cell-surface receptors on neutrophils to mediate some of cortisol's antiinflammatory effects. Previous research has shown that neonatal foals have dramatically increased serum free cortisol levels compared to adult horses, but many septic neonatal foals still exhibit exaggerated pro-inflammatory responses consistent with criticalillness related cortisol insufficiency (CIRCI). This disparity between increased circulating free cortisol but clinical evidence of cortisol insufficiency in some septic neonatal foals could be explained by limited CBG availability in foals, if CBG-bound cortisol is important for regulating some of cortisol's anti-inflammatory effects in foals as in other species. However, our current understanding of cortisol binding dynamics in neonatal foals is limited, and measurement of CBG concentrations in septic foals has not been reported to date.