title: [Some properties of a vasopressor substance generated in human plasma by incubation and its clinical significance in pregnancy-induced hypertension].
abstract: A study to measure the pressor substance, called active pressor principle (APP), which is generated in incubated human plasma was performed using anesthetized and ganglion blocked rats. It was found that APP has properties characteristic of protein. APP was not extractable with mixtures of chloroform: methanol. APP was present at 50 to 70% saturation with ammonium sulfate. By treating the plasma with Pronase, the pressor activity of the plasma was almost completely abolished. The molecular weight of APP as determined by gel filtration was about 68,000. By adding diisopropyl fluorophosphate before incubation of the plasma, the generation of vasopressor substance was prevented. Treatment of the rat with captopril was ineffective in inhibiting the pressor effect of incubated plasma. It was found that the plasma of normal pregnant women generated significantly higher amounts of APP than the plasma of nonpregnant women. The plasma obtained from patients with pregnancy-induced hypertension generated significantly lower amounts of APP than the plasma of normal pregnant women. These findings suggest that a vasoactive protein (APP) is generated during simple incubation of plasma, and a serine protease is involved in the formation of this substance. Concerning the relevance of these results to blood pressure regulation in pregnancy-induced hypertension, probably APP is involved in blood pressure regulation via a compensatory mechanism.
mesh_terms: D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood*; D010712:Phosphatidic Acids / Q000097:blood / Q000502:physiology*; D011225:Pre-Eclampsia / Q000097:blood; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000097:blood*; D014662:Vasoconstrictor Agents / Q000097:blood / Q000502:physiology*
chemical_list: D010712:Phosphatidic Acids; D014662:Vasoconstrictor Agents; C027709:active pressor principle