424 Relation o£ Salts to Carbohydrate Metabolism 



lism appears to be an "over-all" action in the animal body. While the possi- 

 bility of its acting directly on certain enzyme systems has not been entirely 

 excluded, its effects appear at present to be related to endocrine or autonomic 

 nervous functions. When administered in large amounts, Na salts have been 

 shown to increase the deposition of glycogen in the liver of normal, diabetic 

 and adrenalectomized (glucose-fed) rats. There is some evidence to indicate 

 that the rate of oxidation of glucose is simultaneously diminished. In these 

 respects NaCl behaves very much like certain adrenal cortical hormones. Long 

 and his co-workers" have demonstrated that the latter slow up glucose oxida- 

 tion while accelerating the deposition of glycogen in the liver. Since this 

 glycogen-conserving action of Na salts is effective even in totally adrenalec- 

 tomized animals, when they are supplied with glucose, it is obvious that the 

 Na effect is not dependent entirely upon the adrenal gland. Recent experi- 

 ments by Grollman,^* however, emphasize the interdependence between the 

 function of the adrenal cortex and the action of sodium salts. The results of 

 studies by Richter™'^ on the appetites of adrenalectomized rats for NaCl and 

 dextrose likewise indicate the essential interdependence of Na and carbohy- 

 drate metabolism in relationship to adrenal function. 



Data reported by various workers from experiments on normal and diabetic 

 animals, as well as on diabetic human subjects, indicate that Na increases 

 sensitivity to administered insulin. In the intact animal, it may act directly 

 on the insulin-producing mechanism or, on the other hand, it may serve to 

 inhibit the so-called "anti-insulin" or "diabetogenic" mechanisms. Whether 

 or not the production of glycogen is increased at the expense of protein, when 

 Na salts are given in excessive amounts, has not as yet been ascertained; nor 

 has the significance of differences in the effects of Na and K on water balance 

 been fully determined. 



In addition to its supposed roles in the intermediary metabolism of carbo- 

 hydrates, K also appears to act on the intact animal in an "over-all" way with 

 effects antagonistic to those of Na. When administered in comparatively large 

 amounts to normal or diabetic subjects, it inhibits the formation of glycogen 

 or actively promotes glycogenolysis with resulting hyperglycemia and glyco- 

 suria (in diabetics). Whether or not these effects are mediated through neuro- 

 endocrine mechanisms or are due to direct influence on the combined action 

 of the phosphorylase and phosphatase systems, considered by Cori^^ to govern 

 the formation of blood sugar from liver glycogen, cannot at present be said. 



Summary 



Miscellaneous data pertaining to the interrelationships between the exchanges 

 of sodium and potassium and carbohydrate metabolism have been assembled 

 from widely scattered sources. A critical evaluation of the fairly imposing 

 array of evidence thereby made available indicates that these interrelations 

 are of profound significance in both animal and plant economy. 



The "over-all" effects of these two monovalent bases in the animal body have 



