PARATHYROID HORMONE AND RAT CALVARIA METABOLISM 601 



TABLE VI. The Effects of an Uncoupler on Glycolysis 

 (Glucose 17 niM; 2,4-DNP 2 X 10^'* m; bicarbonate medium) 



duction were increased to that found under anaerobic conditions. 

 There was a shght increase in the quantity of exogenous glucose 

 taken up by the tissue, but not enough to account for the increased 

 lactic acid production. It would seem that, in the presence of dini- 

 trophenol, the endogenous supply of carbohydrate is more rapidly 

 glycolyzed. These data also support the conclusion that the TCA 

 cycle is functioning in this tissue and that it is, as in all tissues 

 studied with this uncoupler, intimately linked with glycolysis as far 

 as control is concerned. This point is also deducible from the fact 

 that the Pasteur effect is present both endogenously and when ex- 

 ternal substrate is added. 



Parathyroid Action 



The parathyroid hormone, a purified preparation kindly donated 

 by Dr. Rasmussen, was added in vitro at a level of 5 units per ml, 

 and the various parameters so far described were studied. Because 

 of the increase in citrate production observed in vivo (Firschein 

 et al., 1958 ) , it was sui-prising that no significant alteration in citric 

 acid levels was observed, either in the medium or in the tissue. No 

 effect was noted on glucose uptake or on the Qoo in phosphate me- 

 dium. No significant changes in calcium or phosphate levels in the 

 medium could be demonstrated. 



The only significant finding was that shown in Table VII, an in- 

 crease in the accumulation of lactate in the system. This was found 

 to occur in phosphate and in bicarbonate medium, at low and high 

 levels of glucose, but only under aerobic conditions. The differences 

 between the means, in phosphate medium, have p values of about 

 0.05. If comparisons are made of paired flasks containing the al- 

 ternating halves of the same calvaria, the p values are less than 0.02. 



