ACE and diabetes mellitus: Ramipril has direct effects on the renin-angiotensin-kallikrein system and may prevent diabetes through effects on the beta cell and by vascular and metabolic effects on muscle that may amplify the effects of insulin.[18] The ACE inhibitors increase islet blood flow and pancreatic beta-cell perfusion by reducing angiotensin II-mediated vasoconstriction in the pancreas,[19] which may potentially slow down or reverse the decline in beta-cell function.