Stimulation of Active Renin Release in Normal and Hypertensive Pregnancy

1990 ◽  
Vol 79 (5) ◽  
pp. 505-511 ◽  
Author(s):  
Mark A. Brown ◽  
Vivienne C. Zammit ◽  
Delma Adsett
Keyword(s):  
Pregnant Women ◽  
Plasma Renin ◽  
Normal Pregnancy ◽  
Active Plasma ◽  
Pregnancy Induced Hypertension ◽  
Third Trimester ◽  
Renin Substrate ◽  
Plasma Renin Concentration ◽  
Active Renin ◽  
Induced Hypertension

1. Active plasma renin concentration but not total renin concentration is reduced in women with pregnancy-induced hypertension compared with normotensive pregnant women. This study was conducted to determine whether women with pregnancy-induced hypertension are able to stimulate release of active renin. 2. Active plasma renin concentration was measured as the generation of angiotensin I at physiological pH in the presence of excess renin substrate, and total renin concentration was determined in the same way after trypsin activation. Inactive plasma renin concentration was calculated as the difference between total renin and active plasma renin concentrations. 3. Resting active plasma renin concentration was significantly greater in third-trimester primigravidae compared with normotensive non-pregnant women and active plasma renin and total renin concentrations rose significantly without a fall in inactive plasma renin concentration in both groups after 2 h ambulation, suggesting increased release of active plasma renin and not conversion of circulating inactive to active renin. These responses were blunted in women taking oral contraceptives. 4. Although the active plasma renin concentration was significantly reduced in third-trimester primigravidae with pregnancy-induced hypertension, total renin concentration was not significantly different compared with normotensive women of similar gestation and in both groups 30 min 60° head-up tilt increased active but not inactive plasma renin concentration. 5. These studies show that in normal pregnancy active plasma renin concentration can be stimulated to a similar extent as in non-pregnant women, despite a higher resting level. This appears to be due to increased secretion of active plasma renin rather than conversion of circulating inactive to active renin. Women with pregnancy-induced hypertension are also still able to stimulate secretion of active renin despite resting concentrations similar to those of non-pregnant women. These data suggest that in pregnancy-induced hypertension basal secretion of active renin is prematurely reset to that in the non-pregnant state but that secretion of active renin responds normally to posture.

Soluble Fas and Fas Ligand in Pregnancy

Angiology ◽  
2011 ◽  
Vol 63 (1) ◽  
pp. 35-38 ◽  
Author(s):  
Velore J. Karthikeyan ◽  
Gregory Y. H. Lip ◽  
Sabah Baghdadi ◽  
Deirdre A. Lane ◽  
D. Gareth Beevers ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Fas Ligand ◽  
Normal Pregnancy ◽  
Enzyme Linked Immunosorbent Assay ◽  
Pregnancy Induced Hypertension ◽  
Control Groups ◽  
Pregnancy Hypertension ◽  
Soluble Fas ◽  
Induced Hypertension ◽  
In Pregnancy

The pathophysiology of pregnancy-induced hypertension and preeclampsia may involve abnormalities in placentation and the Fas/Fas ligand system. Hypothesizing abnormal plasma Fas and Fas ligand in pregnancy-induced hypertension, we recruited 20 hypertensive pregnant women at mean week 15 and 29 at week 30: 18 were studied at both time points. Control groups were 20 normotensive pregnant women at week 20, 29 women at week 27, and 50 nonpregnant women. sFas and sFas ligand (sFasL) were measured by enzyme-linked immunosorbent assay (ELISA). The hypertensive women had lower sFasL at both stages of their pregnancy ( P < .05). There were no differences in sFas. In 18 hypertensive pregnant women, sFasL fell from week 15 to week 29 ( P < .03). We conclude that sFas and sFasL is unchanged in normal pregnancy. Hypertension in pregnancy is characterized by low sFasL, and levels fall from weeks 15 to 29. This may reflect differences in placentation in the differing physiological and pathological states.

Neutrophil Platelet-Activating Factor in Normal and Hypertensive Pregnancy and in Pregnancy-Induced Hypertension

1993 ◽  
Vol 85 (1) ◽  
pp. 63-70 ◽  
Author(s):  
L. J. Beilin ◽  
K. D. Croft ◽  
C. A. Michael ◽  
J. Ritchie ◽  
L. Schmidt ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Platelet Activating Factor ◽  
Calcium Ionophore ◽  
Normal Pregnancy ◽  
Pregnancy Induced Hypertension ◽  
Uncomplicated Hypertension ◽  
Control Subjects ◽  
Significant Difference ◽  
Induced Hypertension ◽  
In Pregnancy

1. Platelet-activating factor is a phospholipid with potent vasodilator and platelet-activating properties. To test the hypothesis that a generalized change in cellular platelet-activating factor metabolism may be involved in the systemic vasodilatation of normal pregnancy or pregnancy-induced hypertension, we studied platelet-activating factor and eicosanoid synthesis in isolated leucocytes obtained from pregnant women before and after delivery compared with age-matched non-pregnant control subjects. Parallel observations were carried out in age- and gestation-matched women with uncomplicated hypertension in pregnancy and in women with pregnancy-induced hypertension and a further set of normotensive pregnant control subjects. 2. Leucocyte counts were higher in all pregnant groups compared with non-pregnant control subjects. Neutrophil production of platelet-activating factor and metabolites of prostacyclin, prostaglandin E2 and thromboxane in response to calcium ionophore stimulation were all lower in pregnant women compared with non-pregnant control subjects, but returned to similar levels 6 weeks post partum. There was no significant difference between essential hypertensive and normotensive groups. When women with pregnancy-induced hypertension were a priori subdivided into those with or without proteinuria, subjects with proteinuria showed significantly lower levels of neutrophil platelet-activating factor synthesis. 3. Plasma levels of the platelet-activating factor metabolite (lyso-platelet-activating factor) were also lower in pregnancy, suggesting alterations in the activity of enzymes controlling synthesis or degradation of this phospholipid in pregnancy. In pregnancy-induced hypertension the levels of plasma lyso-platelet-activating factor were higher than in normal pregnancy. 4. Thus this study demonstrates a reduction in the maximum capacity of neutrophils to synthesize platelet-activating factor and the three main classes of eicosanoids in vitro and a reduction in plasma lyso-platelet-activating factor levels in normotensive and essential hypertensive pregnancies. Contrary to expectation neutrophil prostacyclin metabolite generation was reduced in normal pregnancy. In pregnancy-induced hypertension with proteinuria the suppression of neutrophil platelet-activating factor synthesis was more pronounced. The results do not support the involvement of platelet-activating factor in the vasodilatation of pregnancy, but indicate profound changes in cellular phospholipid metabolism in normal pregnancy with further disturbances in pregnancy-induced hypertension by as yet unexplained mechanisms.

Plasma Renin Activity in Normal Human Pregnancy and in Pregnancy-Associated Hypertension, with Reference to Cryoactivation

1980 ◽  
Vol 59 (1) ◽  
pp. 49-53 ◽  
Author(s):  
E. D. M. Gallery ◽  
G. S. Stokes ◽  
A. Z. Györy ◽  
J. Rowe ◽  
J. Williams
Keyword(s):  
Plasma Renin Activity ◽  
Pregnant Women ◽  
Sodium Intake ◽  
Plasma Renin ◽  
Normal Pregnancy ◽  
Renin Activity ◽  
Central Feature ◽  
Plasma Renin Concentration ◽  
Significant Difference ◽  
In Pregnancy

1. Because hypertension is the central feature of pre-eclampsia, and because plasma renin activity is known to be elevated in normal pregnancy (with conflicting results published for pre-eclampsia), a prospective study of plasma renin activity was conducted in pregnancy, under conditions of a fixed sodium intake, in 178 initially normotensive volunteer subjects. Thirty of these women developed pregnancy-associated hypertension (pre-eclampsia) in the third trimester. 2. There was a significant elevation of plasma renin activity from the published values for non-pregnant women, throughout gestation in normotensive women. There was no significant difference, at any stage of gestation, between the values for normal women and those who developed pregnancy-associated hypertension. 3. The extent of cryoactivation of renin, produced by usual collection procedures, was investigated in a subgroup of the total population. It was highly significant and quite variable, but was similar in those who developed pregnancy-associated hypertension and in normal pregnant women. The mean increase in plasma renin concentration in maximally cryoactivated samples was 16-fold. 4. Neither measurement of peripheral plasma renin activity nor of cryoactivatable plasma renin concentration is of value in distinguishing between normal pregnant women and those destined for, or with pregnancy-associated, hypertension.

A ouabain-displacing factor in normal pregnancy, pregnancy-induced hypertension and pre-eclampsia

1988 ◽  
Vol 74 (3) ◽  
pp. 307-310 ◽  
Author(s):  
I. Gregoire ◽  
D. Roth ◽  
G. Siegenthaler ◽  
P. Fievet ◽  
N. El Esper ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Receptor Binding ◽  
Adenosine Triphosphatase ◽  
Binding Assay ◽  
Normal Pregnancy ◽  
Pregnancy Induced Hypertension ◽  
Sodium Potassium ◽  
Receptor Binding Assay ◽  
Induced Hypertension ◽  
In Pregnancy

1. A ouabain-displacing factor (ODF) was measured in the urine of non-pregnant, normotensive pregnant and hypertensive pregnant women by a receptor-binding assay with sodium, potassium-dependent adenosine triphosphatase. 2. Urinary ODF was significantly increased in normal pregnancy. 3. Greater increases were seen in pregnancy-induced hypertension and pre-eclampsia.

Enhancement of plasma corticotropin-releasing hormone in pregnancy-induced hypertension

1990 ◽  
Vol 122 (6) ◽  
pp. 711-714 ◽  
Author(s):  
W. Jeske ◽  
P. Soszyński ◽  
E. Lukaszewicz ◽  
R. Dȩbski ◽  
W. Latoszewska ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Gestational Age ◽  
Placental Tissue ◽  
Normal Pregnancy ◽  
Placental Lactogen ◽  
Control Group ◽  
Pregnancy Induced Hypertension ◽  
Human Placental Lactogen ◽  
Induced Hypertension ◽  
In Pregnancy

Abstract. The role of a high CRH level in normal pregnancy remains unknown. Therefore we evaluated the concentrations of CRH and the related hormones in patients with pregnancy-induced hypertension. Fourteen women with pregnancy-induced hypertension, aged 20-39, at 30-39 gestational week, were investigated. The control group consisted of 20 healthy pregnant women matched according to gestational age. Plasma CRH, β-endorphin-like immunoreactivity, cortisol, and human placental lactogen were measured by radioimmunoassay, ACTH by an immunoradiometric method. It was found that in hypertensive patients the mean CRH concentration was significantly higher (4257±840 (sem) ng/l) than that in healthy pregnant women (1083±227 ng/l, p<0.001). The concentration of ACTH, however, was only slightly higher 65.0±6.0 vs 50.7±2.5 ng/l, p<0.025, whereas the differences in β-endorphin, cortisol and human placental lactogen were not significant. In both groups there was no correlation between the CRH level and those of the related hormones. In healthy pregnant women the CRH level closely correlated with gestational age (r=0.76, p<0.001), whereas in patients with hypertension no such correlation was present (r=0.29). We assume that the marked enhancement of plasma CRH in pregnancy-induced hypertension is probably caused by its decreased breakdown in ischemic placental tissue, but its increased synthesis in the placenta and its indirect counterregulatory hypotensive role must also be considered.

Serum autotaxin measurements in pregnant women: Application for the differentiation of normal pregnancy and pregnancy-induced hypertension

2011 ◽  
Vol 412 (21-22) ◽  
pp. 1944-1950 ◽  
Author(s):  
Akiko Masuda ◽  
Tomoyuki Fujii ◽  
Yuki Iwasawa ◽  
Kazuhiro Nakamura ◽  
Ryunosuke Ohkawa ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Normal Pregnancy ◽  
Pregnancy Induced Hypertension ◽  
Induced Hypertension
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