Cyclic adenosine monophosphate (cAMP) biosensors comprising a Renilla luciferase (RLuc), a green fluorescent protein (GFP), and an exchange protein activated by cAMP, and uses thereof in determining cAMP levels bothin vivoandin vitro. Another aspect of the invention relates to methods for controlling blood glucose levels.本發明係有關環磷酸腺苷(cAMP)生物感測器,其包含水母冷光素酶(RLuc)、綠色螢光蛋白(GFP)、及cAMP活化之交換蛋白,以及其在體內與體外決定cAMP濃度之應用。本發明之另一態樣係有關控制血液葡萄糖濃度之方法。