Radioactive Indicators in the Study of Phosphorus Metabolism in Rats

Abstract

RECENT progress in the production of radioactive isotopes by neutron bombardment makes the radioactive isotope of phosphorus ₁₅P³² easily accessible. This isotope, which has a half-life value of 17 days, can be utilised as an indicator of inactive phosphorus in the same way that the radioactive isotopes of lead, bismuth and so on were formerly used as indicators of these elements. If, for example, we add active ₁₅P³² to 1 mgm. of inactive phosphorus in such quantity that the Geiger counter registers 1,000 impulses per minute, carry out with the phosphorus activated in this way any sort of chemical or biological reaction and then find that the product obtained gives 1 impulse per minute, we may conclude that 1/1,000 mgm. of the phosphorus originally introduced is present in the product investigated.