Measurement of Free Glucocorticoids: Quantifying Corticosteroid-Binding Globulin Binding Affinity and Its Variation Within and among Mammalian Species.

Understanding how wildlife cope with stressors gives us insight into their potential impact. To quantify key hormones of stress - glucocorticoids – one needs to measure both how much there is in plasma (Total) and how much is not bound to a specific binding protein (Free). Here, we layout the first step in calculating FREE – measuring how strongly the specific protein binds the glucocorticoid.