The effect of hydralazine on placental perfusion in the spontaneously hypertensive rat.
Intravenous hydralazine was administered to 16 spontaneously hypertensive rats on day 21 of gestation. The radioactive labeled microsphere technique was used to assess the change in organ perfusion produced by the drug. Vascular resistance to most organs was decreased, except to the placentas, stomach, and cecum, where it increased by 43%, 104%, and 44%, respectively. Blood flow to the organs was redistributed, and although it was increased to the lungs, kidneys, liver, and adrenals, it was significantly reduced to the spleen, stomach, placentas, cecum, large intestine, and pancreas. The effect of hydralazine on placental perfusion was opposite to the effect on the uterus (myometrium). Patients with the highest blood pressures tend to have the poorest placental perfusion. Intravenous hydralazine should be used cautiously in these patients.
D000818:Animals; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D005260:Female; D006830:Hydralazine / Q000627:therapeutic use*; D006973:Hypertension / Q000188:drug therapy*; D010477:Perfusion; D010920:Placenta / Q000187:drug effects*; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000188:drug therapy*; D051381:Rats; D011918:Rats, Inbred SHR
D000959:Antihypertensive Agents; D006830:Hydralazine