The role of sex hormones and sodium intake in postmenopausal hypertension

Abstract

To determine the role of sex hormones and sodium intake in hypertension seen in postmenopausal woman, 12 women (aged 50 to 59 years) in whom blood pressure increased for the first time to above 150/90 mmHg after cessation of menstruation were examined in comparison with 7 age-matched postmenopausal normotensive women (118 +/- 2/62 +/- 3 mmHg). All subjects were admitted to the hospital and their sodium intake was maintained at 204 (normal), 306 (high), and 51 (low) mmol/day for 5 days each. In each period, body weight, blood pressure, heart rate, serum levels of sex hormones and vasoactive hormones, and urinary excretions of sodium, kallikrein and dopamine were determined. The plasma levels of prolactin, progesterone, oestrone, and oestradiol in the hypertensive women were all significantly lower than those in the normotensive women in all study periods. With a change in sodium intake from high to low, blood pressure in 8 out of 12 hypertensive patients decreased by more than 10% from 160 +/- 2/100 +/- 2 mmHg to 144 +/- 2/87 +/- 2 mmHg, while in the normotensive women, only 1 out of 7 patients responded to this change in sodium intake. The changes in sodium intake did not alter the plasma levels of sex hormones in the hypertensive and normotensive subjects. Among the hypertensive patients, three had a history of pregnancy-induced hypertension, while none of the normotensive subjects had such a history. The results of the present study suggest that decreases in sex hormones and increased sensitivity to sodium are important factors in the genesis of postmenopausal hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)