Mx. Wang et al., ENDOTHELIN EXCRETION IN HYPERTENSIVE PREGNANCY - RELATIONSHIP TO GLOMERULAR-FILTRATION RATE, BLOOD-PRESSURE, AND SODIUM-EXCRETION, American journal of hypertension, 7(4), 1994, pp. 308-313
The objective of this study was to determine whether urinary endotheli
n (ET) excretion is altered in pregnant women with preeclampsia or ess
ential hypertension compared with normal pregnant and nonpregnant wome
n, and whether urinary ET excretion is significantly related to glomer
ular filtration rate (GER), blood pressure, or sodium excretion in hyp
ertensive pregnant women. Subjects included 85 hypertensive women in t
heir third trimester (32 with severe preeclampsia, 37 with mild preecl
ampsia some of whom may be classified as having ''transient (gestatio
nal) hypertension'' by other classifications, and 16 with essential h
ypertension), 42 normal third-trimester pregnant women, and 26 normal
nonpregnant women. Twenty-four-hour urine ET and creatinine excretion
were measured in all women. ET was extracted from urine and measured b
y radioimmunoassay. Plasma creatinine, serum uric acid and albumin con
centrations, and urine protein and sodium excretion were also measured
. Twenty-four-hour ET excretion was significantly higher (P < .01) in
normal pregnant women (14.7 9.1 to 20.1 pmol/day; median interquart
ile range) than in nonpregnant women (8.4 6.4 to 15.2 pmol/day) and
was reduced significantly (P < .01) in hypertensive pregnant women (s
evere preeclampsia: 9.0 5.5 to 12.4 pmol/day; mild preeclampsia: 7.2
5.7 to 9.9 pmol/day; essential hypertension: 7.5 6.4 to 9.4 pmol/
day) compared to values for normal pregnant women. Twenty-four-hour ur
ine ET excretion in hypertensive pregnant women was correlated positiv
ely but weakly with both creatinine clearance (r = 0.31, P < .01) and
urine sodium excretion (r = 0.34, P < .01). Urinary ET excretion is in
creased in normal pregnancy and reduced from these values in pregnanci
es complicated by preeclampsia or essential hypertension. This may be
explained partly by reduced filtered ET but must also reflect impaired
renal ET production. There is no evidence for enhanced renal ET produ
ction in preeclampsia.