Iodide 



<59 



particular kind of cell common to the glands where iodide secre- 

 tion is most active. If there is a cytological feature characteristic of 

 iodide-secreting cells this has not yet been identified. 



In the dog submaxillary gland saliva iodide concentrations are 

 normally lower than in the plasma and the relationship of concen- 

 tration of iodide to the rate of saliva flow is unlike that in the 

 parotid. In this secretion the concentration decreases at low flow 

 rates (Fig. 8.1 1) (Burgen and Seeman, 1957). Nothing is known 

 of the mechanism of iodide secretion in this gland. 



10 



WO 800 



300 

 V 



400 500 



Fig. 8.1 1. Saliva/plasma ratio for iodide and chloride. 



V V submaxillary iodide; O — O parotid chloride; • — • parotid iodide when the 



plasma iodide was 2-3 mEq/1. and perchlorate was administered to give a blood concentration of 

 about 2 mEq/1. (Burgen and Seeman, 1957). 



The saliva/plasma ratio of iodide can be self-depressed by 

 rather high concentrations of iodide (greater than 0-5 mEq/1. in 

 the dog) and also by perchlorate, thiocyanate and less effectively 

 by nitrate (Rowlands, Edwards and Honour, 1953; Edwards, 

 Fletcher and Rowlands, 1954; Ferguson, Naimark and Hildes, 

 1957; Burgen and Seeman, 1957). A thorough study of the rela- 

 tionship between these ions has been carried out in vitro with 

 slices of mouse salivary glands (Fletcher, Honour and Rowlands, 

 1957). With this preparation half depression of iodide concentra- 

 tion was found with 2-5 /«M of C10 4 ", 35 //M of I~ or CNS~, and 

 250 jliM of NO3-. Bromide was completely ineffective. These 

 authors make the interesting observation that the concentration of 



