[Role of endothelial cells on refractoriness to angiotensin-II in pregnant and non-pregnant rabbits].
Vascular refractoriness to angiotensin-II (A-II) during pregnancy is well recognized. The present study was designed to evaluate how the response of endothelial cells of arterial rings to A-II changes in pregnant rabbits (n = 24) when compared with non-pregnant rabbits (n = 24). The response of the arterial rings with intact endothelium to A-II was markedly decreased in the pregnant rabbit group in comparison with the non-pregnant rabbit group. In contrast, in the case of the arterial rings whose endothelium had been removed, there was no difference between the two rabbit groups in the response to A-II. However, the maximum response of arterial rings to A-II was significantly lower in the pregnant group than the non-pregnant group under the presence of the endothelium. This study revealed that the arterial rings with intact endothelium prepared from the pregnant group shows markedly increased refractoriness to A-II, while no such difference is seen with rings from which the endothelium had been removed. That is, this study indicated that an endothelium-derived relaxing factor (EDRF) is deeply involved in refractoriness to A-II in pregnant rabbits.
Hidaka
A
A
Department of Obstetrics and Gynecology, Osaka City University Medical School.
Nakamoto
O
O
Kitanaka
T
T
Tomoda
S
S
Sugawa
T
T
D000804:Angiotensin II / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology*; D005260:Female; D066298:In Vitro Techniques; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D011817:Rabbits
D000804:Angiotensin II