Quantitation of P metabolism in the rabbit by means of 32P

Cr2O3 was found to be very effective in correcting the daily variations in the excretion of dry matter, Ca, Mg, and P in rabbit faeces. It can shorten the length of a balance experiment by 50%. We have an idea that a considerable part (about 50%) of the total P retained is incorporated in the organism so quickly that it cannot be observed with the intravenous radioactive tracer method. The excretion of the endogenous faecal P amounted to 20 mg per day. No significant difference was found between the apparent and the actual absorption coefficient of P. The exchangeable P pool of the organism amounted to 690 mg. The experiment results should be subjected to detailed biometric evaluation.