Outflow after Isotope Injections 



21 



gland using the following substances: water (T 2 0), chloride, 

 bromide, iodide, sulphate, bicarbonate, sodium, potassium, urea 

 and four amino-acids (valine, methionine, isoleucine and t\ rosine). 

 Neither sulphate nor any of the amino-acids appeared in detect- 

 able amounts in the saliva but all the other isotopes appeared after 

 more or less brief latencies and reached peak concentrations of 

 the same order. A typical experiment is illustrated in Fig. 10.12. 

 In this case, Br 82 ~ and Na 22+ were injected together — it can be 

 seen that the curves are very much alike but that Br entered the 

 saliva some 10 fA./g earlier than Na and also reached a peak and 

 declined more rapidly. The behaviour of all the substances 

 studied is summarized in Fig. 10.13. Trie earliest substance is tri- 

 tiated water with a latency of 5-10 f-d./g. Its concentration rises 

 rapidly to a peak and then falls off with a half time of 5-10 seconds. 

 Bicarbonate enters the saliva at the same point and has a very similar 

 time course; chloride and bromide are delayed by 3 [A./g but 



40 so sec 



1 



100 , 150 

 Ml/2 



zoo 



Fig. 10.13. The form of saliva outflow curves after intra-arterial injection 

 various substances. 



Note the progressively longer latency from T 2 up to urea (Burger., Terroux and Martin, 



i960). 



of 



