i86 



Organic Constituents of Saliva 



In summary it appears that the salivary a-amino-acids are de- 

 rived from plasma amino-acids because they reflect the plasma 

 concentrations quite accurately, but in addition in human saliva 

 three non-a-amino-acids are present in high concentration and are 

 probably the product of gland metabolism. 



GLUCOSE 



The absence of appreciable amounts of glucose in normal saliva 

 has generally been reported (Pearce, 1916; Johns, 1933; Morris 

 and Way, 1924; Hebb and Stavraky, 1936; Langley, Gunthorpe 

 and Beall, 1958; Pigman and Hawkins, 1958). Pigman and Haw- 

 kins, using chromatographic analysis, found no trace of free 



30 



£: 20 



to 



10 



% 



1 ■ I 1 1 1 r 



200 400 600 



Blood glucose mg/WOml. 



Fig. 9.7. Concentration of glucose in cat submaxillary saliva as the blood 

 glucose concentration was raised. 



No significant concentration was found when the blood level was less than about 

 300 mg/100 ml. (data of Hebb and Stavraky, 1936). 



glucose, glucosamine, N-acetyl-glucosamine or other reducing 

 monosaccharides in saliva, the small amount of dialysable reducing 

 substance present appeared to be a mixture of oligosaccharides. 

 Amberson and Hober (1932) found that small amounts of glucose 

 passed into the saliva in their perfused submaxillary preparations. 

 Hebb and Stavraky (Fig. 9.7) found that when the blood-sugar 

 level exceeded 300 mg/100 ml. small amounts of glucose ap- 

 peared in the saliva, and were proportionate to further increase in 

 the blood concentration. The amounts found were relatively small, 

 for instance at a plasma glucose level of 500 mg/100 ml. the saliva 

 glucose was only 25 mg/100 ml. Langley, Gunthorpe and Beall 



