Estimation of oxidative products of nitric oxide (nitrates, nitrites) in preeclampsia

Oxidative products of nitric oxide, serum nitrates and nitrites were estimated in 50 primigravidas with preeclampsia and in 50 gestation and age-matched normotensive primigravidas. Thirty three (66%) of these women had mild preeclampsia and 17 (34%) had severe preeclampsia. Serum nitrate and nitrite levels were significantly higher in preeclamptic women (nitrates - 15 +/- 1.17; nitrites - 11.82 +/- 1.16 micromol/L) than in the normotensive pregnant women (nitrates 11.82 +/- 1.16; nitrites - 5.08 +/- 0.47 micromol/L, p < 0.001). In preeclamptic women, serum nitrate and nitrite levels correlated with the severity of the disease (mild preeclampsia nitrate - 14.46 +/- 1.98; nitrite 6.21 +/- 0.84 micromol/L, severe preeclampsia nitrate - 16.65 +/- 3.64; Nitrite - 6.87 +/- 1.56 micromol/L). In preeclampsia there was significant positive correlation between nitrate and nitrite levels and diastolic blood pressure and proteinuria.     

Cerebrospinal fluid nitric oxide level changes in preeclampsia

OBJECTIVE: The purpose of this study was to determine the level of nitric oxide (NO) metabolites, nitrite and nitrate in human cerebrospinal fluid (CSF) and serum and to assess whether there is any relationship among CSF, serum nitrate-nitrite levels and preeclampsia. STUDY DESIGN: Twenty-one preeclamptic and 27 healthy pregnant women as control group who underwent cesarean section (C/S) were included in the study. Before administering local anesthetic for spinal anesthesia, 2 ml CSF and 4 ml venous blood sample were taken. CSF and serum total nitrite, direct nitrite and nitrate levels were determined spectrophotometrically. RESULTS: CSF total nitrite, direct nitrite and nitrate levels were significantly different between the two groups (21.00+/-1.68, 8.28+/-0.89 and 12.71+/-1.08 micromol/l, respectively versus 15.53+/-1.49, 5.57+/-0.39 and 9.96+/-1.45 micromol/l, respectively, P<0.05). Significantly higher serum nitrate level was found (31.84+/-2.31 micromol/l) in the control group compared to the preeclamptic group serum nitrate level (25.06+/-2.02 micromol/l). Statistical comparisons were performed by the Mann-Whitney U-test. CONCLUSION: CSF-NO is significantly higher but serum NO is lower in preeclamptic group compared with control group may suggest independent regulation of NO in the two compartments. The determination of CSF-NO metabolites could be useful to clarify whether increased NO production is predominantly associated with poor perfusion of the brain in preeclampsia.     

Maternal circulating nitrite levels are decreased in both normal normotensive pregnancies and pregnancies with preeclampsia.

OBJECTIVE: To evaluate whether maternal nitric oxide synthesis in pregnancies with preeclampsia is different from that in normal normotensive pregnancies. MATERIALS: Maternal circulating combined nitrate and nitrite levels or nitrite level were compared between 10 normotensive nonpregnant women, 30 normotensive pregnant women (10 first-trimester, 10 second-trimester, and 10 third-trimester pregnancies), 20 normotensive postpartum women (10 at 1 week after delivery, and 10 at 4 weeks after delivery), and 13 preeclamptic women (32 to 40 weeks' gestation). End-products of nitric oxide synthesis were measured from maternal venous blood samples using a fluorometric assay. RESULTS: Maternal circulating nitrite levels in nonpregnant women (1.13 +/- 0.22 microM) were significantly higher than those in the first-trimester pregnant women (0.68 +/- 0.13 microM), second-trimester pregnant women (0.65 +/- 0.13 microM), third-trimester pregnant women (0.48 +/- 0.17 microM), first puerperal week women (0.36 +/- 0.16 microM), and fourth puerperal week women (0.67 +/- 0.17 microM), respectively (p < 0.05). Maternal circulating nitrite level was decreased with advancing gestation, still remained low just after delivery, and was increased 4 weeks later. There was no significant difference in maternal circulating nitrite level between preeclamptic women (0.40 +/- 0.17 microM) and third-trimester pregnant women (0.48 +/- 0.17 microM). However, there were no significant differences in maternal circulating combined nitrate and nitrite levels among the groups. CONCLUSION: These results suggest that the maternal nitric oxide synthesis is not changed in normal normotensive pregnancies and pregnancies with preeclampsia. However, plasma nitrite level, which has stronger spasmolytic activity than the activity of the nitrate, was decreased in both normal normotensive pregnancies and pregnancies with preeclampsia.     

Neuropeptide Y and nitrite levels in preeclamptic and normotensive gravid women.

OBJECTIVES: Vascular tone is controlled largely by the sympathetic nervous system and is modulated by neuropeptide Y. Preeclampsia is linked to sympathetic overactivity. Nitric oxide can cause vasorelaxation of vessels or decrease sympathetic outflow by activating the baroreceptor reflex. Our purpose in this study was to compare serum levels of neuropeptide Y and nitrite levels in normotensive and preeclamptic gravid women. STUDY DESIGN: Twelve preeclamptic and 12 normotensive women matched for race, body mass index, parity, and gestational age were studied. Neuropeptide Y was measured by using a commercial radioimmunoassay. Nitric oxide was converted to nitrite by using metallic cadmium, and nitrite levels were determined spectrophotometrically by using a colorimetric assay. Data are presented as mean +/- SEM and were compared by using a t test. RESULTS: Neuropeptide Y levels were similar among preeclamptic and normotensive gravid women (33.8 +/- 3.0 and 32.2 +/- 3 pg/mL, respectively). Similarly, there were no differences in nitrite concentrations between preeclamptic and normotensive patients (11.6 +/- 0.8 vs 11.2 +/- 0.4 micromol/L, respectively). We also examined the ratios of neuropeptide Y and nitrite and found no correlation between preeclamptic and normotensive women. CONCLUSION: Peripheral levels of neuropeptide Y or nitrite do not correlate with preeclampsia. Assessment of sympathetic overactivity in preeclampsia requires an alternate model.     

Nitric oxide production with preeclampsia

OBJECTIVE: To clarify production of nitric oxide with pre-eclampsia. METHODS: Production of nitric oxide and elimination of its metabolites, nitrite and nitrate, determines ultimately the level of those metabolites in plasma of subjects whose diets lack them. We measured simultaneously plasma levels and renal clearance of nitrite and nitrate in 20 women with preeclampsia and in 21 healthy pregnant women. Fifteen preeclamptic gravidas were receiving antihypertensive medication and five received betamethasone 1-4 days before the study. Subjects were prescribed low nitrite and nitrate diets for 24 hours and fasted overnight before collection of plasma and urine samples. Nitrite and nitrate were measured spectrophotometrically by Griess reaction. RESULTS: Preeclamptic women had significantly higher plasma levels of nitrite and nitrate (18.1+/-6.2 micromol/L versus 13.0+/-4.3 micromol/L, mean+/-standard deviation [SD], P = .009), which because renal clearance did not differ (0.6+/-0.3 versus 0.7+/-0.3 mL/s), indicated increased production of nitric oxide with preeclampsia that was unaffected by antihypertensives or betamethasone. The mean plasma level of endothelin-1 was increased (5.1+/-1.4 versus 3.6+/-1.0 pg/mL, P < .001), and urinary output of the prostacyclin metabolite 2,3-dinor-6-keto-prostaglandin F1alpha was decreased (39.1+/-18.0 versus 61.3+/-35.6 ng/mmol creatinine, P = .019) with preeclampsia. These two endothelial markers showed no relation to plasma nitrite and nitrate. CONCLUSION: Nitric oxide production was increased with preeclampsia. The biologic significance of increased production is unknown, but it might be compensation for the vasoconstriction of preeclampsia.     

Serum soluble Fas levels in preeclampsia

OBJECTIVE: To determine if serum soluble Fas levels are altered in women with preeclampsia. METHODS: Thirty-four pregnant women with preeclampsia and 34 normotensive pregnant women were studied. Subjects were matched as much as possible for demographics. Preeclampsia was defined as proteinuric hypertension. Serum soluble Fas levels were measured by enzyme-linked immunoassay. Two-tailed Student t test, chi(2) test, Pearson correlation coefficients, and analysis of variance with post hoc test were used for statistical analyses. RESULTS: Mean serum soluble Fas levels were significantly higher in preeclamptic than normotensive women (10.59 +/- 0.68 U/mL versus 5.65 +/- 0.35 U/mL, P <.001). CONCLUSION: Elevated serum soluble Fas is associated with preeclampsia. Such elevation might indicate protection of maternal T-lymphocyte apoptosis and consequently lead to the maternal immune intolerance noted in preeclampsia.     

Relation between serum uric acid and plasma adenosine levels in women with preeclampsia

The aim of this study was to examine the relationship between plasma adenosine and serum uric acid levels in women with preeclampsia. Maternal arterial blood sampling was performed to measure serum uric acid and plasma adenosine levels in 20 pregnant women complicated by preeclampsia and 22 normal pregnant women at 33-38 weeks of gestation. The average plasma adenosine levels were 0.31 +/- 0.12 micromol/l in the normal pregnant group and 0.45 +/- 0.11 micromol/l in the preeclampsia group. The mean serum uric acid level in women with preeclampsia was 5.9 +/- 0.60 mg/dl, significantly higher than in the normal pregnant women (4.4 +/- 0.69 mg/dl). Positive correlations were found between serum uric acid and plasma adenosine levels in both the group with (r(2) = 0.38, p < 0.05) and the group without (r(2) = 0.54, p < 0.05) preeclampsia. There was also a significant correlation between serum uric acid and plasma adenosine levels on the whole (r(2) = 0.59, p < 0.05). Our results suggest that increased adenosine is a contributing source of preeclamptic hyperuricemia.     

L-arginine infusion reduces blood pressure in preeclamptic women through nitric oxide release.

OBJECTIVE: This study investigates the biochemical and cardiovascular effects of L-arginine administration in normotensive pregnant women and women with preeclampsia. METHODS: The study groups consisted of 12 women with uncomplicated pregnancies and 17 preeclamptic patients, four of whom were on antihypertensive treatment. In both groups, saline infusion was started, followed by 30 g L-arginine administration, and finally more saline. Blood pressure was recorded every 5 minutes and blood samples were collected for measurement of serum citrulline, arginine, and nitrite levels. Amino acid assays were done by using high-performance liquid chromatography with fluorometric detection. RESULTS: L-Arginine infusion was associated with a significant reduction of blood pressure in both groups, the decrease being greater in the women with preeclampsia. Baseline serum citrulline and arginine levels were not significantly different between the two groups. L-Citrulline levels were significantly increased during infusion of L-arginine, and the increase was significantly lower in the women with preeclampsia. Serum nitrite levels were increased only in controls and not in preeclampsia patients. The total citrulline production stimulated by L-arginine was related inversely to baseline blood pressure values and was unrelated to clinical parameters such as gestational age at delivery, birth weight, and Apgar score. CONCLUSIONS: L-Arginine load in pregnant women is associated with increased nitric oxide (NO) production and hypotension. Despite a reduced ability to produce NO, patients with preeclampsia may benefit from L-arginine supplementation. Overall, these findings partially support the hypothesis that preeclampsia is characterized by a dysfunction of the L-arginine-NO pathway.     

Serum Levels of Alpha-Tocopherol in Hypertensive Pregnancies

Objective: Assess alpha-tocopherol serum levels in a population of pregnant women affected by different hypertensive disorders.

Methods: Alpha-tocopherol serum levels were determined by high-pressure liquid chromatography in 177 third-trimester pregnant women: 63 affected by gestational hypertension, 69 by preeclampsia, 26 by chronic hypertension, and 19 normotensive controls. In 39 out of the 158 hypertensive patients, pregnancy was complicated by intrauterine growth retardation (IUGR).

Results: Alpha-tocopherol serum levels did not show any significant difference among gestational hypertensive, preeclamptic, chronic hypertensive patients, and controls. A significant reduction of alpha-tocopherol levels was observed when we compared patients with IUGR and patients with a normally grown fetus. Such significant reduction was maintained when we analyzed the different classes of hypertension.

Conclusions: The reduction of antioxidant nutrients and, in particular, of alpha-tocopherol is not a feature of preeclampsia and seems better correlated with the presence of placental insufficiency, rather than maternal disease.     

Neurokinin B peptide serum levels are higher in normotensive pregnant women than in preeclamptic pregnant women

OBJECTIVES: The purpose of this study was to examine neurokinin B levels in serum from preeclamptic and normotensive and to investigate the role of neurokinin B in preeclampsia. STUDY DESIGN: Peripheral and uterine venous blood neurokinin B levels were measured in 14 normotensive and 8 preeclamptic pregnant women by radioimmunoassay. RESULTS: Neurokinin B levels in normotensive women were 4.91 +/- 2.67 nmol/L in peripheral and 5.59 +/- 2.06 nmol/L in uterine blood. In pregnant women with preeclampsia, neurokinin B levels were 2.79 +/- 1.68 nmol/L and 3.20 +/- 1.55 nmol/L, respectively. Neurokinin B levels were significantly higher in normotensive women (P=.032 in peripheral and P=.006 in uterine blood). CONCLUSIONS: Neurokinin B serum levels were higher in normotensive women. Higher neurokinin B concentrations in normotensive pregnant women may be due to the advanced gestational age and/or the result of a negative interaction of other vasoactive substances. The role of neurokinin B in preeclampsia remains to be determined.     

Nitric oxide production is not altered in preeclampsia

Background Preeclampsia remains a disease of theories as the real aetiology has remained elusive. Altered nitric oxide production has been associated with preeclampsia although conflicting results showing elevation, decrease or no change in nitric oxide levels have emerged from previous studies. Objective The aim of the study was to measure the serum levels of nitrate and nitrite in normal pregnancies and pregnancies complicated by pre-eclampsia. Materials and methods Venous blood was extracted from 39 normal pregnant women (control) and 34 women with preeclampsia (study group). Serum concentrations of nitrate and nitrite were determined using the HPLC method. Other special investigations including renal function tests were performed. The patients were managed according to protocol and the outcome of the pregnancies evaluated. Results There was no significant difference in the mean maternal age and gestational age at delivery between the groups. However the mean systolic and diastolic blood pressure of the study group (150.5 mmHg and 98.8 mmHg) were significantly higher than the levels in the control group, (110.86 and 85.5), p<0.0001. There was no significant difference in the mean serum nitrate levels (19.157±13.407 vs. 19.189±16.805) p=0.993. The fetal and maternal outcomes were comparable. Conclusion Our study has demonstrated that there was no alteration in nitric oxide production in preeclampsia, thus contributing to the existing unresolved role of nitric oxide in the pathogenesis of preeclampsia. Further research is called for.     

Immunoreactive circulating endothelin-1 in normal and hypertensive pregnancies.

OBJECTIVE: The purpose of this study was to measure the circulatory levels of endothelin-1 in the serum of pregnant women with hypertension. STUDY DESIGN: Endothelin-1 levels were measured by means of radioimmunoassay in the serum of 26 pregnant women with hypertension (14 with pregnancy-induced preeclamptic toxemia, 12 with chronic hypertension) and in the serum of 17 control pregnant women and 18 control nonpregnant women. The mean levels in the different groups were subject to statistical analysis with the analysis of variance. RESULTS: The mean level among the women with preeclampsia (29.9 +/- 13.2 fmol/ml) was significantly higher than those of the chronically hypertensive women (16.1 +/- 7.3 fmol/ml, p = 0.002) and of the control pregnant women (19.7 +/- 9.2 fmol/ml, p = 0.011). The mean level of the control nonpregnant women (26.9 +/- 9.3) was significantly higher than that of the control pregnant women (p = 0.029). Among the patients with preeclampsia there was no correlation between endothelin-1 levels and the mean arterial blood pressure. Six to 10 weeks after delivery the mean levels of 15 studied patients (7 with preeclampsia, 8 with chronic hypertension) were similar to the levels of the nonpregnant control women. CONCLUSION: We conclude that increased endothelin-1 production may play a role in the pathogenesis of preeclampsia.     

Elevated amniotic fluid leptin levels in pregnant women who are destined to develop preeclampsia

OBJECTIVE: To analyze whether leptin levels of the amniotic fluid elevate during early pregnancy in women destined to develop preeclampsia and to evaluate the relationship between amniotic fluid leptin levels and gestational age, maternal body mass index, and fetal sex. STUDY DESIGN: Leptin levels of the amniotic fluid were compared in two groups of women, preeclamptic (n = 20) and normotensive pregnant (n = 40), matched for fetal sex, maternal body mass index at sampling, gravidity and fetal gestational age at sampling. Furthermore, amniotic leptin levels in 400 normotensive pregnant women were analyzed for their correlation with gestational age, maternal body mass index, and fetal sex. RESULTS: Median leptin concentrations were significantly higher (p < 0.001) in the women with preeclampsia (7.3+/-0.7 ng/ml) than in the normotensive pregnant women (4.1 +/- 0.3 ng/ml), independent of fetal sex. The leptin levels in the amniotic fluid decreased with advanced gestational age (r = 0.24, p < 0.001). Amniotic fluid leptin levels in the pregnant women carrying a female fetus (5.6+/-0.3ng/ml) were significantly higher than those carrying a male fetus (4.7+/-0.2 ng/ml) (p = 0.004). CONCLUSION: Higher amniotic fluid leptin levels were observed in the preeclamptic pregnant women, and they decreased as gestational age advanced. Furthermore, the women with a female fetus were noted to have higher amniotic fluid leptin levels.     

A comparative study of serum soluble vascular cell adhesion molecule-1 and soluble intercellular adhesion molecule-1 in preeclampsia.

OBJECTIVES: Maternal serum soluble vascular cell adhesion molecule-1 (sVCAM-1) and soluble intercellular adhesion molecule-1 (sICAM-1) were evaluated in preeclampsia to investigate whether these molecules could be helpful with regard to this pregnancy complication. STUDY DESIGN: The study population was composed of 30 preeclamptic patients with a mean gestational age of 35.5 +/- 4.6 weeks and 20 age-matched and gestational age-matched normotensive uncomplicated pregnancies (controls). Blood samples from 7 of the 30 preeclamptic patients and 15 of the 20 controls in the second trimester were also analyzed. Data were analyzed by parametric methods. RESULTS: Significantly higher maternal serum sVCAM-1 levels were found in both groups of preeclamptic patients with and without fetal growth restriction (981 +/- 145 ng/ml; n = 13; p < 0.0005 and 846 +/- 84 ng/ml; p < 0.02, respectively) compared with controls (668 +/- 186 ng/ml). In contrast, no significant difference was found in maternal serum sICAM-1 levels between preeclamptic and normotensive pregnancies, or in both adhesion molecules (1) in the controls between second and third trimester samples and (2) in the second trimester between pregnant women who developed preeclampsia later and gestational age-matched controls. CONCLUSION: These findings show a selective significant elevation of maternal serum sVCAM-1 in preeclampsia, with the highest values in cases complicated with fetal growth restriction, perhaps reflecting its angiogenic function. Hence, sVCAM-1 could be helpful in the diagnosis of this fetal complication in preeclampsia.     

Maternal serum activin A is not elevated before preeclampsia in women who are at high risk

OBJECTIVE: The purpose of this study was to determine whether, in women who are at high risk of the development of preeclampsia, serum activin A concentrations are elevated before the disease and whether activin A is a useful predictor of preeclampsia. STUDY DESIGN: Sera were collected on five occasions throughout pregnancy from women with chronic hypertension, renal disease, or previous early-onset preeclampsia (n = 80 women). Women were classified as control subjects (normotensive or stable chronic hypertension), gestational hypertensive, or preeclamptic (de novo or superimposed). Serum activin A concentrations were measured by immunoassay. Differences in activin A concentrations between groups were analyzed with the use of a mixed-models procedure; screening test characteristics were calculated. RESULTS: Twenty-six women (33%) had gestational hypertension, and 17 women (21%) had preeclampsia or superimposed preeclampsia. Serum activin A levels increased with gestation in all groups (P =.0001), but there were no significant difference in activin A levels between groups (P =.75). CONCLUSION: In women who were at high risk of the development of preeclampsia, serum activin A levels are not elevated with preeclampsia. Activin A is not a useful predictor of preeclampsia in this setting.     

Plasma nitric oxide levels and the expression of P-selectin on platelets in preeclampsia

OBJECTIVE: The purpose of this study was to investigate the correlation of plasma nitric oxide levels with the expression of P-selectin on platelets in preeclampsia. STUDY DESIGN: Plasma levels of nitrite and nitrate (the stable nitric oxide metabolites) and the expression of P-selectin on platelets (a platelet activation marker) were measured in 25 normal pregnant women and 25 women with preeclampsia. The effects of the inhibition of nitric oxide synthesis on the expression of P-selectin also was measured in vitro. RESULTS: Plasma nitrate levels and the expression of P-selectin averaged 30.5 +/- 2.2 micromol/L and 8.9% +/- 1.1% (SEM), respectively, in preeclampsia, which was significantly higher than in normal pregnancy (P <.05). Nitric oxide synthesis inhibition in vitro significantly increased the expression of P-selectin in normal pregnancy by 284% (P <.05), which was significantly higher than in preeclampsia (156%, P <.05). CONCLUSION: The inhibitory effects of increased nitric oxide on the expression of P-selectin is attenuated in preeclampsia, which may contribute partly to the pathogenesis of preeclampsia.     

Maternal plasma adenosine and endothelin-1 levels in twin gestation complicated by preeclampsia

The aim of this study was to evaluate the relationship between the vascular resistance in uterine arteries and the maternal release of adenosine and endothelin-1 in twin gestations with and without preeclampsia. Uterine artery Doppler velocimetry and maternal arterial blood sampling were performed in 14 women with normal singleton gestation, nine women with singleton gestation with preeclampsia, eight women with dichorionic twin gestation without preeclampsia and six women with dichorionic twin gestation with preeclampsia at 28–34 weeks’ gestation. In normal singleton gestations, the average maternal uterine arteries pulsatility index (PI), plasma adenosine and endothelin-1 levels were 0.64±0.07, 0.34±0.11 μmol/l and 1.29±0.31 pg/ml, respectively. In preeclamptic singleton gestations, increased vascular resistance in the uterine arteries (PI: 0.85±0.14, P<0.05) and the elevation of maternal arterial plasma adenosine (0.48±0.14 μmol/l, P<0.05) and endothelin-1 levels (1.91±0.55 pg/ml, P<0.05) were observed. In the normal twin gestation group, the average maternal vascular resistance of the uterine arteries (PI: 0.55±0.09) was lower than that in the normal singleton gestation group, while the average plasma adenosine levels (0.47±0.12 μmol/l) were higher than that in normal singleton gestation. On the other hand, significant increased plasma endothelin-1 concentrations (1.87±0.42 pg/ml) were observed in the preeclamptic twin gestation groups without changes in plasma adenosine levels or vascular resistance of uterine arteries. Our results indicate the presence of different mechanisms for the pathogenesis of preeclampsia between twin and singleton gestations. Received: 5 October 2001 / Accepted: 3 December 2001 Correspondence to S. Suzuki     

Amniotic fluid and maternal serum leptin levels in pregnant women who subsequently develop preeclampsia

OBJECTIVES: To study the correlation between amniotic fluid leptin levels and maternal serum leptin levels during the early second trimester, and to determine whether the ratios of amniotic fluid leptin levels to maternal serum leptin levels are elevated in pregnant women who subsequently develop preeclampsia. STUDY DESIGN: Samples from 120 pregnant women were included in this prospective study, of which 20 were from pregnant women who subsequently developed preeclampsia and 100 were from normal pregnant women. Both the amniotic fluid and the maternal serum leptin levels were ascertained by radioimmunoassay (RIA). RESULTS: A strong correlation between amniotic fluid leptin levels and maternal serum leptin levels was observed in both preeclamptic and normal pregnant women. In addition, the ratios of amniotic fluid leptin levels to maternal serum leptin levels were positively correlated to amniotic fluid leptin levels, but negatively correlated to maternal serum leptin levels. Furthermore, the ratios of amniotic fluid leptin levels to maternal serum leptin levels in preeclamptic women were significantly higher than those in normal pregnant women. CONCLUSIONS: Amniotic fluid leptin levels correlated with maternal serum leptin levels during the early second trimester. The ratios of amniotic fluid leptin levels to maternal serum leptin levels were elevated in preeclamptic women. However, the maternal serum leptin levels themselves showed no such elevation. Therefore, this elevated ratio may be a marker at the early stage of pregnancy in preeclamptic women.     

Bioactivity of serum hCG in preeclampsia

OBJECTIVE: To compare hCG levels, obtained by biologic and immunologic means, in women with normal pregnancies and women with preeclampsia. METHODS: Peripheral blood samples from women in the third trimester with preeclampsia (n = 30) or normal pregnancies (n = 30) were assayed for immunoactive and bioactive hCG (mouse Leydig cell testosterone production assay). RESULTS: Serum bioactive hCG levels tended to be lower than normal, and immunoactive hCG levels tended to be higher in women with preeclampsia, but the differences were not statistically significant. However, the ratio of bioactive to immunoactive hCG was significantly lower than normal for preeclamptic women (0.70 +/- 0.28 vs. 1.15 +/- 0.35 for normotensive pregnant women [mean +/- standard deviation], P <.001). CONCLUSION: The ratio of bioactive to immunoreactive serum hCG is lower among preeclamptic than among normotensive pregnant women.     

L-Arginine erythrocyte transport in normal pregnant and preeclamptic women

OBJECTIVE: Uptake of L-arginine by the cell via amino acid transporter systems is the first step for nitric oxide (NO) production. The current study aimed to assess the total L-arginine uptake in erythrocytes of normal pregnant and preeclamptic women. STUDY DESIGN: Twenty-one normal pregnant and 21 preeclamptic women were studied. To measure total L-arginine uptake in erythrocytes, carbon 14 was used as a marker and Michaelis-Menten kinetic parameters (V(max) and K(m)) were evaluated. RESULTS: In preeclamptic women, there was a significant increase (P<.004) in the mean maximal capacity of transport in erythrocytes (V(max)=982.69 micromol/L cells/h+/-433.51) in comparison with normal pregnant women (V(max)=584.73 micromol/L cells/h+/-422.33). No significant difference was detected in the half-saturation constant (P=0.978). CONCLUSION: The transport kinetics of the NO precursor, L-arginine, is altered in erythrocytes of preeclamptic women. It is possible that abnormal L-arginine uptake may contribute to the pathophysiologic mechanisms of preeclampsia syndrome.