There are provided a method for selection of a substance which is capable of controlling activation of prorenin where an adjusting ability of the activation of prorenin by protein-protein interaction in a profragment region of prorenin as indicator is used; a prorenin activation controlling substance having a function of controlling the activation of prorenin based on protein-protein interaction by a profragment region of prorenin; and hypotensor, organ hypertrophy suppressor and arterial thickening suppressor containing the prorenin activation controlling substance as an effective ingredient.