The level of blood kinins, their creation and inactivation after one exposure to intense ultraviolet radiation in rabbits.

Experimental rabbits were exposed to ultraviolet radiation once for 45 minutes, and blood samples were obtained from the carotid artery in these animals 45 min and 3, 6 and 24 hours after the end of this exposure. In the group of control rabbits blood samples were obtained in the same way without previous exposure to radiation. The hairs on the back were cut closely at the skin and this skin area was exposed to ultraviolet rays from a Hanau Q 400 burner at 405--289 nm wavelengths and at an intensity of 134 000 erg/sec/cm2, using an UG 2 T Schott filtre and an absorber of long-wave radiation. Blood samples were taken under thiopental anaesthesia. In the samples the level of free kinins was determined in the blood, and the level of kininogen and the activity of kallikreins and kininases were determined in the plasma. In the irradiated animals a rise of the kinin level was observed, with a fall in the kininogen level most pronounced after 3 hours, while the activity of kallikreins was raised and that of kininases was decreased particularly after 6 hours.