Premium
Evidence of dysfunctional β 2 ‐adrenoceptor signal system in pre‐eclampsia
Author(s) -
Aune B.,
Vårtun Å.,
Øian P.,
Sager G.
Publication year - 2000
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.2000.tb11587.x
Subject(s) - eclampsia , medicine , endocrinology , receptor , venous blood , pregnancy , gestational age , gestation , preeclampsia , biology , genetics
Objectives To determine how β 2 ‐adrenoceptor binding and function differ between healthy women and those with pre‐eclampsia. Design Case‐control study. Setting Faculty of Medicine, University of Tromsø, Norway. Participants Two groups of pregnant women: eight cases with pre‐eclampsia, matched with eight healthy controls. Methods Venous blood was drawn from women in both groups after an overnight rest. The two groups were matched for gestational age which was (mean (SD)) 36.4 (3.8) and 36.5 (4.4) weeks for the pre‐eclamptic and control groups, respectively. Six weeks after delivery a second blood sample was obtained. The binding and function of β 2 ‐adrenoceptors were determined in isolated human mononu‐clear leukocytes. The levels of adrenaline and noradrenaline were determined in plasma from venous blood. Results An elevated density of functional β 2 ‐adrenoceptors was observed in normal pregnancy [mean (SD) 390 (90) vs 270 (60) sites/cell postpartum], due to an increased fraction of receptors in high affinity state, with unaltered total receptor density. The number of functional β 2 ‐adrenoceptors was reduced in pre‐eclampsia [mean (SD) 80 (40) vs 240 (30) sites/cell postpartum], due to a reduction in the total receptor number with an unaltered fraction of high affinity receptors. In pregnancy, both unstimulated and isoprenaline‐stimulated cAMP levels were reduced in the women with pre‐eclampsia (0.5 (0.2) and 1.7 (0.9) pmol/10 6 cells, respectively) compared with the normal pregnant controls (mean (SD) 1.2 (0.3) and 4.7 (1.8) pmol/10 6 cells, respectively). Plasma catecholamine levels were not elevated in the women with pre‐eclampsia. Conclusions The increased number of functional β 2 ‐adrenoceptors may contribute to the vasodilatation seen in normal pregnancy, while the reduced overall number of receptors may be one of several factors that account for increased peripheral vascular resistance in pre‐eclampsia.