Endothelin excretion in hypertensive pregnancy. Relationship to glomerular filtration rate, blood pressure, and sodium excretion.

The objective of this study was to determine whether urinary endothelin (ET) excretion is altered in pregnant women with preeclampsia or essential hypertension compared with normal pregnant and nonpregnant women, and whether urinary ET excretion is significantly related to glomerular filtration rate (GFR), blood pressure, or sodium excretion in hypertensive pregnant women. Subjects included 85 hypertensive women in their third trimester (32 with severe preeclampsia, 37 with mild preeclampsia [some of whom may be classified as having "transient (gestational) hypertension" by other classifications], and 16 with essential hypertension), 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 by radioimmunoassay. Plasma creatinine, serum uric acid and albumin concentrations, 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 [interquartile range]) than in nonpregnant women (8.4 [6.4 to 15.2] pmol/day) and was reduced significantly (P < .01) in hypertensive pregnant women (severe 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 urine ET excretion in hypertensive pregnant women was correlated positively but weakly with both creatinine clearance (r = 0.31, P < .01) and urine sodium excretion (r = 0.34, P < .01). Urinary ET excretion is increased in normal pregnancy and reduced from these values in pregnancies complicated with preeclampsia or essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)