Hormone and cAMP measurement

For the measurement of plasma GLP-1, blood samples were collected in ice-cooled BD Microtainer blood collection tubes coated with K2EDTA (36784, BD) followed by addition of 50 µM DPP-IV inhibitor (DPP4, Merck/millipore), while culture medium was collected plus 1% DPP-IV inhibitor and centrifuged for 5 min at 4 °C at 12,000 × g. Active GLP-1 levels were determined by using an active GLP-1 ELISA kit (EGLP-35K, Merck/millipore) according to the manufacturer’s instructions. For the measurement of insulin, a mouse insulin ELISA kit (EZRMI-13K, Merck/millipore) was used. For the measurement of serum levels of total T3, a T3 (total) (Mouse/Rat) ELISA Kit (KA0925, Abnova) was used. For the measurement of GIP, a Rat/Mouse GIP (total) ELISA kit (EZRMGIP-55K, Merck/millipore) was used. For the measurement of cAMP, cAMP was extracted from frozen intestine tissue samples by lysis buffer and analyzed by a mouse cAMP Assay kit (ab138880, Abcam). Intracellular cAMP was extracted from STC-1, NCI-H716 cells and intestinal organoids, and then analyzed according to the manufacturer’s instruction.