Blood pressure and plasma renin activity after magnesium supplementation in the spontaneously hypertensive rat: a study during developing and established hypertension.

The effects of a dietary magnesium supplementation have been studied both on systolic blood pressure and plasma renin activity in the spontaneously hypertensive rat (SHR). This study has been conducted in young (developing hypertension) and mature (established hypertension) male SHR fed during 6 weeks with a normal magnesium diet or with a high magnesium diet. After 6 weeks of diets, the systolic blood pressure was lower in young and mature SHR fed with an increased dietary amount of magnesium than in the young and mature SHR fed with a normal amount of dietary magnesium. Plasma renin activity was similar after the two different diets in young SHR while it was greater in mature SHR receiving a high magnesium diet than in mature SHR receiving a normal diet. Hence, dietary supplementation with magnesium inhibits the development of hypertension in young SHR, and reduces arterial blood pressure in mature SHR. The hypotensive effect observed during magnesium supplementation is not related to an inhibition of the renin release.