1 88 



Organic Constituents of Saliva 



Hober (1932) and Burgen (1956). They found that small molecules 

 of high lipoid solubility penetrated into the saliva with ease but 

 that when the molecular radius exceeded 3-2 A, or the oil/water 

 distribution ratio was less than o-ooi, only small amounts ap- 

 peared in the saliva. For example, the minimum saliva to plasma 

 ratio for mannitol was 0-02, for creatinine 0-05, glycerol o-io, and 



co- 



40- 

 30- 







io 



Fig. 9.8. Results showing relation between saliva-plasma ratios X 100 for 

 ten non-electrolytes in dog parotid saliva secreted at different rates. 



Ordinates: Saliva-plasma ratio X ioo. 



Abscissae: Saliva flow as % of the maximum rate. 



Flow rate varied by changing the frequency of auriculo-temporal stimulation. Maximum rate 

 averaged 0-55 ml./g./min. 



1, thiourea; 2, ethylurea; 3, N-methylurea; 4, urea; 5, glycerol; 6, chloramphenicol; 7, 4-acet- 

 amidoantipyrine, 8, creatinine; 9, methenamine; 10, mannitol (Burgen, 19566). 



urea 0-4; sucrose was not detectable at all in the saliva. On the 

 other hand, the lipoid soluble molecules acetamide, propionamide, 

 butyramide and malonamide passed into the saliva quite easily. 

 Killman and Thaysen (1955) found that in a series of sulphona- 

 mides the ease of penetration into the saliva could be related to the 

 percentage of non-ionized form of the molecules present. They 

 also found that traces of p-aminohippurate appeared in saliva but 

 that inulin did not. Burgen analysed in detail the behaviour of ten 



