556 



ADVENTURES IN RADIOISOTOPE RESEARCH 



Table 1. — Excretion of Labelled Potassium 

 Administered by Mouth 



Time 



Percentage of '^K recovered in tlie 

 urine 



12 



30 



3 



16 lA 

 401/2 



481/4 



mm. 



hours 



0.0053 



0.048 



0.46 



0.65 



4.75 



3.00 



1.56 



Total 10.47 

 Volume of urine = 2.041 cc. 



of non-labelled potassium atoms migrated from the cells into the extra- 

 cellular space. 



In the two following experiments, besides determining the percentage 

 of ^^K administered which was excreted in the course of 65^ hours and 

 the potassium content of the urine, urine samples were collected on three 

 consecutive days between 9 and ll^^ hours and their activity and potas- 

 sium content were determined. The results of these experiments are seen 

 in Tables 2 and 3. While no pronounced difference in the specific activity 

 of the potassium collected after 15, 39 and 63 hours is observed, in the 



Table 2. — ^-K Content of Urine Samples 



Total urine volume = 2.990 cc. 



Percentage of the i-K administered present in the total urine 



12.7 per cent. 



early phases of the experiment potassium of higher specific activity 

 was excreted than in the later phases. This follows from the higher value 

 found for the specific activity of the average potassium present in the 

 mine collected. 



1 cc. urine collected between 9 a. m. and llYo a. m. was found to 

 have an appreciably higher potassium content than 1 cc. of average 



