Search

1. The effect of oestradiol alone and in combination with indomethacin on blood pressure, erythrocyte cation concentration and Na(+)-K+ flux has been studied in adult female normotensive and spontaneously hypertensive rats. 2. Oestradiol alone resulted in a significant decrease in blood pressure in spontaneously hypertensive rats (from 165.3 +/- 3.9 to 146.4 +/- 2.7 mmHg, P less than 0.001), whereas it induced a significant increase in normotensive rats (from 111.8 +/- 1.8 to 124.1 +/- 3.6 mmHg, P less than 0.001). When indomethacin and oestradiol were administered simultaneously or when indomethacin was given alone, no change in blood pressure occurred in spontaneously hypertensive rats (158.6 +/- 6.9 and 159.8 +/- 6.2 mmHg, respectively). 3. The fall in blood pressure induced by oestradiol in spontaneously hypertensive rats was associated with significant reductions in erythrocyte K+ concentration (from 127.4 +/- 1.2 to 116.9 +/- 1.7 mmol/l of cells, P less than 0.001), in erythrocyte Na+ concentration (from 14.3 +/- 0.8 to 13.0 +/- 0.6 mmol/l of cells, P less than 0.02), in ouabain-sensitive erythrocyte Na+ flux (from 17.8 +/- 0.3 to 16.0 +/- 0.4 mmol h-1 (l of cells)-1, P less than 0.01) and in ouabain-sensitive erythrocyte K+ flux (from 11.4 +/- 0.2 to 10.4 +/- 0.2 mmol h-1 (l of cells)-1, P less than 0.01). No change in blood pressure, erythrocyte cation concentration or Na(+)-K+ flux occurred when oestradiol and indomethacin were given together or when indomethacin was administered alone.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of sodium depletion on body weight, plasma renin activity (PRA) and plasma aldosterone concentration has been studied in 10 normotensive subjects with a previous history of pregnancy-associated hypertension. The results demonstrate an appropriate increase in PRA but a suppression of plasma aldosterone response to this form of acute sodium depletion. The significance of this dissociated renin-aldosterone response is discussed.

The effect of an isotonic saline infusion on urinary sodium excretion and plasma renin activity (PRA) has been studied in 11 normotensive patients with a previous history of pregnancy-associated hypertension. The results have been compared with a group of controls matched for age, sex and parity. The results demonstrate an exaggerated natriuresis and a suppressed PRA response in the patients with a previous history or pregnancy-associated hypertension which is similar to those reported in patients with established 'essential' hypertension.