NUCLEIC ACID IX SARCOMA SLICES 771 



sections from rats — v. hich was also observed in one of our early investiga- 

 tions (paper 27) — and, to a small extent, in the cerebral pulp; 300 mgm 

 of nerve substance was immersed in 5 ml of Ringer's solution containing 

 the radioactive phosphate; after 4 hr from 0.44 to 0.72 per cent of the 

 activity was present in the phosphatides isolated from 1 gm of fresh nerve 

 substance. The amount of phosphatide formed during the 4 hr of the 

 test cannot be calculated from these data but the above figures indicate 

 the formation of a not inconsiderable amount of radioactive, and there- 

 fore, new phosphatide molecules in the isolated nerve. Control experi- 

 ments showed that the detected activity was not due to impurities and 

 also provided evidence^^^ that the formation of radioactively labelled 

 phosphatide molecules in the liver and kidney sections was lowered 

 considerably in the presence of cyanide, azide, hydrogen sulphide or 

 carbon dioxide. 



In a later investigation it was also found^^Hhat the formation of phos- 

 phatide molecules containing P^^ jg considerably increased (about five- 

 fold) on the addition of glucose, galactose, mannose or fructose to the 

 Ringer's solution containing the radioactive phosphate. It was possible 

 to demonstrate that this increase is to be attributed essentially to an 

 increased phosphatide metabolism and not to accelerated entry of phos- 

 phate molecules into the nerve cells. When the tissue was removed from 

 the radioactive Ringer's solution after some time and immersed in a 

 similar inactive solution, there was additional formation of radioactive 

 phosphatide in the nerve tissue only in the presence of glucose and not, 

 on the contrary, in a glucose-free solution. The promoting effect of the 

 glucose on the formation of new phosphatide molecules is presumably 

 connected with the increased oxygen consumption of the cerebral tissue 

 in the presence of glucose. The oxygen consumption of the tissue remains 

 unchanged for a very long time when the solutions contain glucose but 

 decreases rapidly in glucose-free Ringer's solution. 



The formation of other compounds, e. g. di-iodotyrosin and thyroxin, 

 in the tissue sections, as well as the formation of phosphatide molecules, 

 was also found by Chaikoff and co-workers^*^ to be related to the unin- 

 hibited oxygen consumption of the tissue. Inhibition of cytochrome- 

 oxidase by means of cyanide or other impurities has been shown to be 

 harmful to the synthesis of new molecules in tissue sections of the thyroid 

 gland. We shall emphasize at this point that the formation of ^ap-contain- 

 ing deoxyribose molecules in sarcoma sections observed by us is distur- 

 bed by the presence of cyanide, fluoride or monoiodoacetate. 



W S. A. Fries, H. Schachneb and J. L. Chaikoff, J.Biol. Chem. 144, 59 (1942). 

 (2) A. Taurogg, J. L. Chaikoff and J. Perlman, J. Biol. Chem. 145, 281 (1942). 

 (3^ H. ScHACHisrER, V. A. Fries and J. Chaikoff, J. Biol. Chem. 146, 95 (1942). 

 (*^ H. ScHACHNER, A. L. Franklin and J. L. Chaikoff, J. Biol. Chem. 151, 

 (1943). 



49=* 



