RADIOPHOSPHORUS 



214 



RADIOSODIUM 



phosphate ion: 4-23% is eliminated in 

 24 hrs. in urine and feces. Rate falls 

 to less than 1% per day after 3d day. 

 The retention of radiophosphorus varies 

 in different tissues. In decreasing 

 order the activity of the element ap- 

 peared in bone, muscle, liver, stomach 

 and small intestine, blood, kidneys, 

 heart, lungs and brain. The turnover 

 of radiophosphorus in brain is much 

 slower than in other tissues. On basis 

 of weight retention it is highest in bone, 

 liver, intestinal tract, heart, kidneys, 

 lungs, blood, muscle, skin, and brain 

 (in decreasing order). Scott, K. G. 

 and Cook, S. F., Proc. Nat. Acad. Sci., 

 1937, 23, 285-272 found that large doses 

 of P^2 cause decrease in polymorpho- 

 nuclear leukocytes in circulating blood 

 of chicks, presumably due to selective 

 beta ray irradiation of the bone mar- 

 row in consequence of higher absorption 

 and retention in bone. Lawrence and 

 his group (Lawrence, J. H. and Scott, 

 K. G., Proc. Soc. Exp. Biol. & Med., 

 1939, 40, 694-696; and Lawrence, J. H., 

 Tuttle, L. W., Scott, K. G., Conner, 

 C. L., J. Clin. Invest., 1940, 19, 267- 

 271), as result of this finding, com- 

 pared phosphorus metabolism of normal 

 and leukemic mice. Although the total 

 phosphorus content of lymph nodes, 

 spleen, and liver was about the same in 

 normal and leukemic animals, the pro- 

 portion of P^2 in the leukemic animal 

 was distinctly higher, indicating a 

 higher rate of phosphorus metabolism 

 in these animals. Lawrence, J. H., 

 Radiology, 1940, 35, 51-60 reported the 

 use of radiophosphorus on a group of 

 patients suffering from leukemia and 

 polycythemia. Hevesy, G. and Lunds- 

 gaard, E., Nature, 1927, 140, 275-276 

 and Arton, C, Sarzana, G., Perrier, C, 

 Santangelo, M. and Segr6, E., Nature, 

 1937, 139, 836-837 have studied conver- 

 sion of inorganic phosphates to phos- 

 pholipids. They observed different 

 rates of synthesis and storage in various 

 organs. Studies on phospholipids using 

 P^2 as tracer are reviewed by Sinclair, 

 R. G., Biol. Symposium, 1941, 5, 82-98. 

 Chaikoff and his colleagues (numerous 

 papers in J. Biol. Chem., 1937 and fol- 

 lowing years) confirmed these results 

 on different animals and extended 

 studies to isolated tissue slices in vitro. 

 Jones, H. B., Chaikoff, I. L. and 

 Lawrence, J. H. (J. Biol. Chem., 1939, 

 128, 631-634) found different types of 

 malignant tumors had characteristic 

 patterns of phospholipid metabolism 

 not related to cell types. Marshak 

 separated cell nuclei from cytoplasm 

 and observed malignant cell nuclei 

 accumulated more P'^ than normal 

 nuclei and that relative to cytoplasm 



malignant nuclei took up more than 

 normal cells, comparing lymphoma cells 

 with normal liver cells (Marshak, A., 

 Science, 1910, 92, 460-461 and J. Gen. 

 Physiol., 1941, 25, 275-291). This com- 

 bination of the techniques using tracers 

 and methods of separating components 

 of cells offers great promise for further 

 investigation. Numerous reports on 

 plant tissues and on insects are also 

 available. Manly, M. L. and Bale, 

 W. F. (J. Biol. Chem., 1939, 129, 125- 

 134) have described P^- distribution in 

 rat bones and teeth. Sognnaes, R. F. 

 and Volker, J. F., Am. J. Physiol., 1941, 

 133, 112-120 have studied distribution 

 of P^^ in parts of the teeth of cats, dogs, 

 and monkeys. Most P^^ is found in 

 dentin, and little in enamel. Of that in 

 enamel, highest concentration is in 

 outermost layer, suggesting that some 

 minerals reach the teeth by diffusion 

 from saliva. Radiophosphorus may be 

 used to "label" erj^throcvtes in much 

 the same manner as radioiron is used. 

 Recently Brown, Jr., F. A., Hempel- 

 man, Jr., L. H. and Elman, R. have 

 used such "tagged" erythrocytes to 

 determine true blood volume (Science, 

 1942, 96, 323-324). 



Radiopotassium (K«) half life 12.4 hrs. 

 Rate of absorption of radiopotassium 

 from the gut was investigated in con- 

 junction with the study of radioiodine 

 by Hamilton. The distribution of in- 

 jected radiopotassium in tissues of the 

 rat has been studied by Noonan, T. R., 

 Fenn, W. O. and Haege, L. (Am. J. 

 Physiol., 1941, 132, 474-488). An early 

 concentration of the ion occurs in liver, 

 heart, kidney, lung, diaphragm, and 

 gastrointestinal tract. After equilib- 

 rium is reached, most of the radio- 

 activity is present in tissues normally 

 high in potassium, i. e. muscle, skin and 

 viscera. Recently Lyman, C. P., Am. 

 J. Physiol., 1942, 137, 393-395 employing 

 this isotope has demonstrated an in- 

 creased permeability of clenervated 

 skeletal muscle to potassium ion. 



Radiorhubidium (Rb^^) half life IS days. 

 It is possible that radiorhubidium can 

 be used in place of radiopotassium which 

 is difficult to prepare but no work ap- 

 pears to have been reported as yet. 



Radioselenium (Se'^) half life 48 days. 

 McConnell, K. P., J. Biol. Chem., 1941, 

 141, 427-437 has reported on the reten- 

 tion of radioselenium in various tissues. 

 19% is found in the liver; considerable 

 amounts in muscle, intestine, and blood ; 

 less in the testis. None is present in 

 the skin, fur, teeth, and long bones. 

 The element is chiefly excreted by the 

 kidneys. 



Radiosodium (Na^^) half life 14.8 hrs. 

 Easiest element to prepare. The yield 



