Ma. Brown et al., CONTROL OF ALDOSTERONE IN NORMAL AND HYPERTENSIVE PREGNANCY - EFFECTSOF METOCLOPRAMIDE, Hypertension in pregnancy, 12(1), 1993, pp. 37-51
To test whether factors other than angiotensin II (AII) are important
in the control of aldosterone during pregnancy, we examined the inhibi
tory effects of dopamine upon aldosterone release during normal pregna
ncy in women with pregnancy-induced hypertension (PIH) and in normal a
ge-matched non-pregnant women, using the dopamine antagonist metoclopr
amide. Plasma renin (PRC), plasma aldosterone (PAC), and serum cortiso
l concentrations were measured before and 30 minutes after intravenous
metoclopramide in 6 non-pregnant women during both phases of their me
nstrual cycle, 6 women taking oral contraceptive pills (OCPs) during b
oth halves of their menstrual cycle, 6 normal third-trimester primigra
vidas and 9 women with PIH. All were sodium replete and eating an adli
bitum diet. Six pregnant and 6 non-pregnant women served as controls a
nd had the same measurements before and after 2 ml intravenous saline
instead of metoclopramide. Baseline PRC, PAC and cortisol were higher
in normal pregnant than non-pregnant women and PRC was reduced signifi
cantly from values for normal pregnancy in those with PIH. Serum corti
sol was elevated significantly in women taking OCPs compared with othe
r non-pregnant women (P < 0.05). PAC increased following metoclopramid
e in every subject, but PRC and cortisol remained unchanged. PAC, PRC
or cortisol were not altered significantly over the same time period i
n control subjects. Although the percentage increment in PAC following
metoclopramide was greater in women with PIH than in normal pregnant
women (P <0.05), absolute changes were not significantly different bet
ween these two groups. Our findings demonstrate that dopamine exerts c
onsiderable inhibitory influence upon aldosterone release in both non-
pregnant and pregnant women despite markedly elevated aldosterone conc
entration in pregnancy. This effect is apparent in both normotensive p
regnant women and in those with PIH.