[Width of radiation protective effects of indralin in comparative studies using different animal species]

In the experiments on mice, rats, hamsters, guinea pigs, dogs and Macaca Rhesus ED50, the width of radioprotective effect of indralin from alpha-adrenomimetics was investigated. It was made an estimate by ED50, LD50 and therapeutic index (TI): ED50/LD50. ED50 of indralin i.m. on mice is 21.9 (16.2-29.4) mg/kg, on guinea pigs --28.8 (17.0-49.0) mg/kg, on hamsters --50.7 (42.9-59.8) mg/kg and on dogs --6.0 (4.3-8.3) mg/kg. TI of indralin i.m. for same animals is correspondingly equal to 23.7 (15.3-36.5), 25.6 (13.7-47.4), 17.8 (14.8-24.1) and 31.1 (20.6-47.3). TI of indralin p.o. for rats and dogs is close to 18.2 and 23.7. Under the equal conditions TI of cystamine for mice, rats (i.p.) and dogs (i.v.) is respectively 3.3 (2.82-3.70), 2.1 (1.57-2.82) and 1.22. T50 of the elimination of indralin on mice (100 mg/kg i.p. and i.m.) for toxicologic properties measured circa 5-10 min. Under the conditions of repeated application in 30-60 min indralin desensitization to toxic doses happened as the rise of LD50 by 15-30%. T50 of the elimination of indralin in optimum doses for the pharmacodynamic of radioprotective effect is 19.3 (13.3-28.0) min on mice, --19.2 (15.3-25.9) on hamsters, --26.9 (20.4-35.5) on rats and --40.2 (30.5-53.1) min on dogs. In the transition from the experiment on mice to dogs twofold rise of T50 of the elimination of indralin doesn't combine with adequate increase the toxicity of the radioprotector. Pathophysiologic foundation of distinctions between aminothiols and radioprotector realizing the effect through cell receptor in the width of radioprotective effect is discussed.