Metabolism cage,” glass

The required data generally are obtained by administering a measured dose of the candidate compound -- often isotopically labelled -- to the rat or mouse either by injection or per os. The animal is housed in a glass metabolism "cage" where it receives food, water, and clean air, and its urine, feces, and respired gases are collected and examined for the parent chemical and its metabolites. Eventual postmortem tissue analysis and calculation of material balance complete the measurements necessary to satisfy the above purposes of metabolism and pharmacokinetic experiments. While in vitro biochemical studies are important adjuncts, it is also apparent that only experiments with intact, healthy, living animals will suffice to meet EPA criteria. 

The radiolabelled peptide under study was administered to rats as described above. The animals were then placed in separate glass metabolic cages, allowing reliable separation of urine and solid excreta. The animals had free access to standard diet and water. Two hours after injection of the peptide, the rats urinary bladders were emptied manually, and the urine and faeces were collected. The procedure was repeated at 24 and 48 h post-injection. 

Air input. 2. Soda lime for absorption of carbon dioxide. 3. Flow-meter. 4. Metabolism cage. 5. Three-way glass stopcock. 6. Liquid scintillation counter. 7. Photomultipliers. 8. Counting vial. 9. Peristaltic pump. 10. Towards barium hydroxide for C02 absorption. 

Normal mice were placed in a glass metabolism cage that permitted the collection of expired CO, and were fed ad libitum a high carbohydrate diet containing glucose-C. At the end of 24 or 48 hr., the mice were... 

---