[CO2 storage in various organs during chronic experimental hypercapnia (author's transl)]

The total CO2 is titrated in liver, abdominal and leg's muscles, brain and thigh-bone of rats exposed to 8 +/- 1% of carbon dioxide under normoxic (20-23% of O2) and normobaric conditions during zero, two, four or six weeks. Total (H2Ot) and extracellular (H2Oe) water is measured in these organs by the 3H-inulin method. The CO2 storage in organs is expressed in relation to the PaCO2 increase (mmol-kg-1 fresh tissue-torr-1). During a four week hypercapnia, this CO2 increase is very important in bone and brain compared with that of other organs and of the whole body. With regard to the whole body, the bone CO2 content is still increasing after four weeks. The increase in extracellular bicarbonate (delta[HCO3-e]/delta PaCO2) is negligible (1/100 th) in comparison with the whole carbonic increase (delta CO2/delta PaCO2). The bone extracellular compartment diminishes in relation with the experimentation duration, without any significant change in H2Oi (Student's analysis). A factorial analysis (BENZECRI) shows that the weight of H2Oe in the information diminishes for all organs, both with the duration of normal subjects observation (ageing) and with the hypercapnia duration.