Vitamin D receptor-null mice had a sustained elevation of renin expression, maintaining a normal level of blood electrolytes [19]. Increased renin synthesis leads to an elevated angiotensin II production, which is a strong vasoconstrictor, enabling the development of hypertension and left ventricular hypertrophy [19].Similarly, 1-alphahydroxylase deficient mice, unable to synthetize the active metabolite 1,25-dihydroxyvitaminD, develop also high blood pressure and left ventricular hypertrophy[4]. Studies using renal arteries from hypertensive patients reported that calcitriol
reduces the expression of the angiotensin-1 receptor in endothelial cells, improving endothelial function and preventing reactive oxygen species overproduction [22].