Blood Pressures in Pregnant Ovariectomized Spontaneously Hypertensive Rats

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Conference Proceeding

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There is a significant decline in hypertensive blood pressure of spontaneously hypertensive rats (SHR) during the last five days of gestation, and it has been suggested that this decline is due to the anti-aldosterone effects of progesterone. Since the ovaries of the rat are the prime source of progesterone during gestation, this study was designed to determine the effects of ovariectomy on the pattern of blood pressure in pregnant SHR. Experimental SHR were ovariectomized on day 12 of gestation. Control SHR were sham operated on the same day of gestation. Animals were checked daily for signs of abortion. Blood pressures were then monitored daily until 20 days gestation when all animals were autopsied. Two or three days post-ovariectomy, all experimental animals had a bloody vaginal discharge indicating abortion. Autopsy revealed viable fetuses in the controls and their placentas were normal. In experimental SHR, a variable number of resorptions were evident and at least one near normal placenta was present in each animal. While the blood pressure of the controls declined at the end of gestation, that of the experimentals did not. Thus, the removal of ovarian hormonal support or fetal loss during gestation does not cause a decline in the blood pressure pattern of the pregnant SHR. (This project was supported by the Miami Valley Chapter of the American Heart Association).


Poster presented at the 93rd Annual Meeting of the Ohio Academy of Science, Case Western Reserve University and The Cleveland Museum of Natural History, Cleveland, OH.

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