MECHANISM OF PARATHYROID HORMONE ACTION 



TABLE IV. Effect of Serum Calcium Concentration 

 ON Production of C"02 



583 



" Mean serum calcium 8 mEq/liter more than in control. 



the bone. The other finding of significance is that of the effect of 

 the calcium treatment on the kidney. In this tissue there was an in- 

 crease in CO2 production, but of a nonspecific nature, since there 

 was no differential between carbons of position 1 and position 6 

 of glucose. This further indicates that the differential after treatment 

 with the hormone resulted from a metabolic alteration. 



The second study to rule out the effect of high concentrations of 

 serum calcium was carried out on parathyroidectomized rats. C^O^ 

 production from glucose-6-C^^ by slices of rat bone in vitro was not 

 influenced by pretreatment of normal animals with parathyroid ex- 

 tract. However, C^^02 production was reduced with bone from 

 parathyroidectomized donors. It was normal with bone from such 

 rats treated with parathyroid extract ( Table V ) . 



It is important to consider whether or not the increased CO12 



TABLE V. Effect of Parathyroidectomy on Production 

 OF C"02 BY Bone 



