Effects of sensitizers on cell respiration: 1. Factors influencing the effects of hypoxic cell radiosensitizers on oxygen utilization of tumour and cultured mammalian cells.
We have investigated the effects of 24 nitrocompounds, differing in their half-reduction potential, on the respiration in vitro of Ehrlich ascites tumour cells and cultured V79 lung cells. Many drugs with redox potentials more positive than--0.35 stimulated oxygen utilization in the presence of glucose. Glucose had little effect on the inhibition of respiration by drugs with oxidation-reduction potentials more negative than--0.38. Nitrocompounds that inhibited Ehrilch cell respiration in the presence of glucose, also inhibited intracellular reduction of ferricytochrome (c+c1). Drugs that stimulated oxygen utilization also stimuated intracellular (c " c1). Drugs that stimulated oxygen utilization also stimulated intracellular reduction of ferricytochrome (c + c1). A correlation between drug oxidation-reduction potential and stimulation of oxygen utilization in KCN-inhibited cells was found.
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism*; D002478:Cells, Cultured; D003574:Cytochrome c Group; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000378:metabolism; D009574:Nitro Compounds / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents
D003574:Cytochrome c Group; D009574:Nitro Compounds; D011838:Radiation-Sensitizing Agents; D005947:Glucose