Release of activatable kallikrein by isolated rat kidneys.

Rat isolated kidneys were perfused for 60 minutes with a modified Krebs-Henseleit bicarbonate solution. Perfusate and urine samples showed kininogenase activity (active kallikrein) which could be enhanced by activation with trypsin (activatable kallikrein). Identification of the kininogenase activity generated by trypsin was made with rat renal kallikrein antiserum, aprotinin, lima bean trypsin inhibitor (LBTI), soybean trypsin inhibitor (SBTI), and ovomucoid. A sample of perfusate was partially purified through DEAD-Sephacel chromatography. Intraarterial injection of this fraction decreased blood pressure in the perfused hind limb of a rat.