[Influence of estrogen and progesterone on the vascular response to angiotensin-II in non-pregnant rabbit vessels--intact or denuded endothelium].
During pregnancy, vascular sensitivity to A-II is reduced and it was clarified that this refractoriness to A-II is due to a change in EDRF output in pregnant rabbits. The present study aimed at elucidating whether estrogen or progesterone is responsible for the augmentation of EDRF output. 17-OH-estradiol was administered (200 micrograms/kg/day) for 7 days to 8 non-pregnant rabbits, while progesterone was similarly administered (2,000 micrograms/kg/day) to 8 other non-pregnant rabbits. Twenty-four nonpregnant rabbits were employed as the controls. Common iliac arterial rings prepared from each group were compared for the isometric response to A-II. The arterial rings with intact endothelium prepared from the progesterone-treated group were found to have a smaller pD2 value and a smaller maximum response to A-II than the estrogen-treated group. On the other hand, no differences between the progesterone group and estradiol group were observed in these values for the endothelium-denuded arterial rings. These findings indicated that the augmentation of EDRF output during pregnancy is brought about by progesterone.
Hidaka
A
A
Department of Obstetrics and Gynecology, Osaka City University School of Medicine.
Nakamoto
O
O
Kitanaka
T
T
Tomoda
S
S
Sugawa
T
T
D000804:Angiotensin II / Q000494:pharmacology* / Q000502:physiology; D000818:Animals; D004967:Estrogens / Q000494:pharmacology / Q000502:physiology*; D005260:Female; D007083:Iliac Artery / Q000187:drug effects; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009569:Nitric Oxide / Q000378:metabolism* / Q000502:physiology; D011374:Progesterone / Q000494:pharmacology / Q000502:physiology*; D011817:Rabbits
D004967:Estrogens; D000804:Angiotensin II; D009569:Nitric Oxide; D011374:Progesterone