544 



ADVENTURES IN RADIOISOTOPE RESEARCH 



After the lapse of 20 minutes, an easily detectable part of the labelled phosphorus, 

 was thus fovind in the urine amounting to 0.1 per cent of the labelled P administered. 

 From the rate of urine production by the subject in question, we can conclude that 

 only about 10 cc. urine were produced in the course of the experiment, 80 cc. 

 being already present at the beginning of the experiment in the bladder. By taking 

 account of the latter, the specific activity of the P found in the urine formed within 

 the first 20 minutes, work out to be 0.0068, i. e. each mgm P found in the urine, 

 produced within the first 20 min after drinking the labelled sodium phosphate 

 solution, contained 0.0068 per cent of the phosphorus atoms present in the latter. 



Table 4 



Time after administration 

 of the labelled P in hours 



Volume of urine 

 in cc. 



Specific activity of urine P 



The fourth male subject investigated, 50 years old, excreted daily 730 cc. 

 xirine containing 790 mgm P. The daily excretion was high, namely 21.1% per cent 

 in the course of the first and 6.4 per cent in the course of the second day. The 

 specific activities are seen in Table 4. 



In another set of experiments 5 cc. of a physiological sodium chloride solution 

 were injected into the veins of each of twelve human subjects. The solution con- 

 tained 1 mgm P as sodium phosphate, and also ^sp showing an activity of 10~5 

 milliCurie. We carried out these experiments to find out if the percentage of the 

 activity, excreted within the first 24 hours tlirough the kidneys, varies much 



Table 5a. — Labelled P Administered per Mouth. Age 

 OF Female Subject 28 Years, Weight 65 kgm 



Time after adminis- 

 tration of labelled P 

 in days 



Total volume 

 in liter 



Total P content 

 in gm 





% of total activity 

 administered, present 

 in urine 



0—15 

 15—39 

 39—52 

 52—76 



14.98 

 25.25 

 12.98 

 25.58 



7.787 



14.400 



8.239 



9.093 



10.3 

 5.3 

 3.6 

 1.5 



Excretion of labelled P in the course of 76 days 20.8 per cent. 

 Total P excretion in urine 39.519 gm. 

 Daily P average excretion 0.520 gm. 



