Magnesium sulfate therapy in preeclampsia is associated with increased urinary cyclic guanosine monophosphate excretion.
OBJECTIVE
Our objective was to determine if maternal urinary cyclic guanosine monophosphate levels are altered in preeclampsia.


METHODS
Aliquots from 24-hour urine samples collected from 57 women with preeclampsia and 14 normotensive pregnant women in the third trimester of pregnancy were assayed for urinary cyclic guanosine monophosphate. Urinary cyclic guanosine monophosphate values were expressed per milligram of urinary creatinine to standardize for renal function.


RESULTS
There was no difference in gestational age at time of urine collection between the two groups. Urinary cyclic guanosine monophosphate levels (mean +/- SD) were similar between normotensive and preeclamptic pregnant women (751 +/- 498 vs 632 +/- 363 pmol/mg urinary creatinine, respectively, p = 0.12). Preeclamptic women receiving magnesium sulfate had significantly higher levels of urinary cyclic guanosine monophosphate than those not receiving magnesium sulfate (786 +/- 360 vs 555 +/- 344 pmol/mg urinary creatinine, respectively, p = 0.02).


CONCLUSIONS
These preliminary results indicated that cyclic guanosine monophosphate excretion increases in patients with preeclampsia during magnesium sulfate infusion. The vascular smooth muscle relaxation effects of magnesium sulfate may be mediated by directly increasing cyclic guanosine monophosphate production or indirectly through endothelium-derived relaxing factor.
Barton
J R
JR
Department of Obstetrics and Gynecology, University of Tennessee, Memphis.
Sibai
B M
BM
Ahokas
R A
RA
Whybrew
W D
WD
Mercer
B M
BM
D006152:Cyclic GMP / Q000652:urine*; D005260:Female; D005865:Gestational Age; D006801:Humans; D008278:Magnesium Sulfate / Q000627:therapeutic use*; D011225:Pre-Eclampsia / Q000188:drug therapy* / Q000652:urine; D011247:Pregnancy; D011863:Radioimmunoassay
D008278:Magnesium Sulfate; D006152:Cyclic GMP