Cortisol-mediated potentiation of uterine artery contractility: effect of pregnancy.
During pregnancy, maternal plasma cortisol concentrations approximately double. Given that cortisol plays an important role in the regulation of vascular reactivity, the present study investigated the potential role of cortisol in potentiation of uterine artery (UA) contractility and tested the hypothesis that pregnancy downregulated the cortisol-mediated potentiation. In vitro cortisol treatment (3, 10, or 30 ng/ml for 24 h) produced a dose-dependent increase in norepinephrine (NE)-induced contractions in both nonpregnant and pregnant (138-143 days gestation) sheep UA. However, this cortisol-mediated response was significantly attenuated by approximately 50% in pregnant UA. The 11 beta-hydroxysteroid dehydrogenase (11-beta HSD) inhibitor carbenoxolone did not change the effect of cortisol in nonpregnant UA but abolished its effect in pregnant UA by increasing the NE pD(2) in control tissues from 6.20 +/- 0.05 to 6.59 +/- 0.11. The apparent dissociation constant value of NE alpha(1)-adrenoceptors was not changed by cortisol in pregnant UA but was decreased in nonpregnant UA. There was no difference in glucocorticoid receptor density between nonpregnant and pregnant UA. Cortisol significantly decreased endothelial nitric oxide (NO) synthase protein levels and NO release in both nonpregnant and pregnant UA, but the effect of cortisol was attenuated in pregnant UA by approximately 50%. Carbenoxolone alone had no effects on NO release in nonpregnant UA but was decreased in pregnant UA. These results suggest that cortisol potentiates NE-mediated contractions by decreasing NO release and increasing NE-binding affinity to alpha(1)-adrenoceptors in nonpregnant UA. Pregnancy attenuates UA sensitivity to cortisol, which may be mediated by increasing type-2 11-beta HSD activity in UA.
Xiao
Daliao
D
Center for Perinatal Biology, Department of Pharmacology and Physiology, Loma Linda University School of Medicine, Loma Linda, California 92350, USA.
Huang
Xiaohui
X
Bae
Soochan
S
Ducsay
Charles A
CA
Zhang
Lubo
L
D042842:11-beta-Hydroxysteroid Dehydrogenases; D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000502:physiology*; D001667:Binding, Competitive; D015153:Blotting, Western; D002229:Carbenoxolone / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005263:Femoral Artery / Q000187:drug effects / Q000502:physiology; D006854:Hydrocortisone / Q000097:blood / Q000494:pharmacology / Q000502:physiology*; D006913:Hydroxysteroid Dehydrogenases / Q000037:antagonists & inhibitors / Q000378:metabolism; D066298:In Vitro Techniques; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D009638:Norepinephrine / Q000494:pharmacology; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000097:blood / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000032:analysis / Q000378:metabolism; D012756:Sheep; D014599:Uterus / Q000098:blood supply* / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*
D004791:Enzyme Inhibitors; D011942:Receptors, Adrenergic, alpha; D011965:Receptors, Glucocorticoid; D009569:Nitric Oxide; D006913:Hydroxysteroid Dehydrogenases; D042842:11-beta-Hydroxysteroid Dehydrogenases; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D002229:Carbenoxolone; D006854:Hydrocortisone; D009638:Norepinephrine