TRAUMATIC SHOCK. VI. THE EFFECT OF HEMORRHAGIC SHOCK ON THE CONCENTRATION OF RENIN AND HYPERTENSINOGEN IN THE PLASMA IN UNANESTHETIZED DOGS 1

Abstract

A study was made of the renal humoral pressor mechanism, in unanesthetized dogs in shock, from the removal of 4 to 5% of the body wt. of blood. It is confirmed that readily detectable amts. of renin appear in the circulating plasma. The conc. of hypertensinogen in plasma decreases in severe shock, sometimes to extremely low levels. Since in shocked dogs which had been ncphrectomized, the concs. of hypertensinogen remained unchanged or increased, it is assumed that ita diminution in shocked dogs with intact kidneys is due mainly or solely to the presence of excessive amts. of renin. Transfusion of 4-5% of body wt. of whole blood, with nearly its normal titer of hypertensinogen, did not increase the conc. of hypertensinogen in plasma appreciably, presumably due to its almost immediate conversion to hypertensin by the large amt. of circulating renin. The renal humoral pressor mechanism is considered to represent a compensatory measure, on the part of the body, to main-tain normal blood pressure in dogs rendered hypotensive by hemorrhage. This mechanism functions inadequately, however, due to the inability of the organism to synthesize hypertensinogen as rapidly as it is converted to hypertensin by the large excess of circulating renin.