Calorie-restricted weight reduction, blood pressure, and atrial natriuretic peptides.

Calorie restriction with resultant weight loss lowers arterial blood pressure in obese people. The mechanism of this blood-pressure reduction has been unknown, but recent evidence suggests that the atrial natriuretic peptide hormonal system may play a role in the blood-pressure changes associated with calorie-reduction-induced weight loss. This newly described hormonal system consists of a 126-amino acid (aa) prohormone synthesized primarily in the heart with a 98-aa NH2-terminal and a 28-aa COOH-terminal of this prohormone released into the circulation. Four peptides consisting of aa 1-30, 31-67, 79-98, and 99-126 of this prohormone each have blood-pressure-lowering properties. The circulating concentrations of these peptides increase in people with high blood pressure in an apparent attempt to overcome the constriction of blood vessels. With calorie-induced weight reduction, the elevated levels of these peptides decrease and correlate in a linear fashion (p < 0.001) with blood-pressure reduction. During this blood-pressure reduction, plasma aldosterone and plasma renin activity inversely correlate with the concentration of atrial natriuretic peptides and blood pressure. This observation is consistent with the ability of atrial natriuretic factor (i.e., aa 99-126 of the prohormone) to inhibit renin release and aldosterone secretion from the adrenal gland. The atrial natriuretic peptide hormonal system appears to be important in blood-pressure regulation in people who are at their ideal body weight and in those who are overweight.