The term '-pressin' refers to which action?

The term '-pressin' is derived from the Latin root "premere," which means "to press." In medical terminology, this suffix is commonly associated with substances or hormones that have a function of constricting or pressing down, particularly when referring to hormones like arginine vasopressin, which has roles in regulating blood pressure and water retention in the body. Thus, the action indicated by '-pressin' aligns with the function of pressing down, making it the correct choice. Understanding this term is important in medical contexts where the actions of various hormones play significant roles in physiological processes.