Oxygen Uptake and Cardiovascular Response of Mice and Rabbits Administered "Hematoporphyrin."

Abstract

Summary The toxicity of several preparations of “hematoporphyrin” has been studied in female ZBC mice and in rabbits. The MLD₁₀₀ in mice ranged from 0.2 to 0.7 mg per gram body weight depending on source of the porphyrin and route of administration. The intraperitoneal route was generally most toxic. A marked fall in total body oxygen uptake associated with severe hypotension and decreased blood flow occurred at lethal or near-lethal dose levels. In vitro measurement of oxygen uptake by mouse liver homogenates showed no effect at porphyrin concentrations up to 3 × 10^-4M (5 mg/gram of liver in a 10% liver homogenate) at pH 7.4 to 8.9 but 50 per cent or more depression at pH 6.5 to 6.6. Associated phenomena and some implications of these results in relation to studies on the modification of radiosensitivity by porphyrins are considered.