“…15,16 Insulin is a protein hormone secreted by b cells in pancreatic islets in response to stimulation by endogenous or exogenous substances such as glucose, lactose, ribose, arginine, glucagon and so on. 17 As an externally secreted protein, it is synthesized in ribosomes 18 with subsequent processing in the endoplasmic reticulum and Golgi apparatus. Communication between the Fig.…”