In vivo measurement of variations in the oxygen 18 content of water in rat brain.
A method of analysis for oxygen 18 is described, based on the anodic oxidation of specially prepared tantalum wires implanted through cannulas into the tissue of living animals. The thin anodic oxide layer formed on these wires is then analyzed by the 18O(p,alpha)15N reaction. The isotopic oxygen concentration of water in the brain obtained by this method compares very well with the values obtained by conventional analysis using mass spectrometry. This in vivo method of nuclear microanalysis has been used in both metabolic and equilibration experiments involving oxygen 18. The half-life for the turnover of 18O in body water was found to be about 3 days. A simple three-pool model is presented which can account for the experimental results obtained from the dilution by body water of interperitoneally injected water highly enriched in 18O.
D000818:Animals; D001834:Body Water / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D004567:Electrodes, Implanted; D008297:Male; D008722:Methods; D008962:Models, Theoretical; D010101:Oxygen Consumption; D010103:Oxygen Isotopes; D051381:Rats
D010103:Oxygen Isotopes