Chronic CO2 Toxicity: Species Difference in Physiological and Histopathological Effects
Medical research progress rept. no. 8
NAVAL SUBMARINE MEDICAL RESEARCH LAB GROTON CT
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Guinea pigs were found to have a much higher susceptibility to carbon dioxide than rats. During exposure to CO2 concentrations ranging from 1-50 CO2, marked species differences were observed in mortality, growth curves, organbody weight ratios and serum enzyme responses. The difference in tolerance to CO2 between guinea pigs and rats has been related to their differing buffer capacity. Guinea pigs showed higher levels of hydrogen ion concentrations for every exposure. No evidence of tissue necrosis in heart, liver, and other organs was obtained in guinea pigs or rats exposed for prolonged periods to 15 CO2. The increased levels of serum enzymes GPT, GOT, LDH observed in guinea pigs under these conditions were interpreted as signs of increased permeability caused by hypercapnia. An organ specific pattern of fat accumulation was observed in chronic hypercapnia.