THE SUPRARENAL SYSTEM 2IQ 



site of the direct action of adrenalin is to be found in those fibres 

 of the sympathetic, the central irritation of which produces effects 

 similar to those of puncture of the fourth ventricle. Through the 

 agency of the sympathetic system, adrenalin increases the tone 

 of the vessels, and in a similar manner it increases the sugar-tone 

 (Zuckertonus) that is to say, it increases the concentration of the 

 sugar in the blood, so producing hyperglycaemia, which is 

 followed by glycosuria. 



Blum first pointed out the similarity which exists between the 

 effects of Claude Bernard's puncture and the glycosuria produced 

 by adrenalin, and he suggested that the former is expressed 

 through the agency of the suprarenals. A. Meyer next showed 

 that puncture of the floor of the fourth ventricle does not produce 

 glycosuria in rabbits from which the suprarenals have been 

 removed; and more recently, Waterman and Smit found that 

 puncture of the floor of the fourth ventricle, similarly to stimu- 

 lation of the sympathetic, increases the amount of adrenalin 

 present in the blood. The far-reaching analogy between the effects 

 of puncture of the fourth ventricle and experimental adrenalin 

 glycosuria, is still further confirmed by the experiments of 

 Eppinger, Falta, and Rudinger. These showed that, if the 

 thyroid gland is extirpated, in neither condition does glycosuria 

 result; but that a mobilization of carbohydrates takes place, as 

 shown by the decreased excretion of nitrogen, and that this is 

 consumed by the agency of the now hyper-active pancreas. A 

 further similarity between the two conditions is shown by the 

 behaviour of dogs from which the pancreas has been removed. 

 These animals showed increased glycosuria and hyperglycasmia, 

 both after puncture of the fourth ventricle (Hedon and Kaufmann), 

 and after the exhibition of adrenalin. The authors conclude from 

 these results, that the excretion of sugar after puncture of the 

 fourth ventricle represents a discharge from the chromaffine 

 system. 



The difference in the processes by which glycosuria and hyper- 

 glycasmia result from puncture of the fourth ventricle and from 

 the exhibition of adrenalin, lies in this : that, in the case of 

 adrenalin, the results are brought about by peripheral stimulation 

 of the sympathetic ; after puncture of the fourth ventricle they are 

 due to stimulation of the sympathetic centres. 



L. Pollak found that, after resection of the splanchnic nerve, 

 adrenalin invariably produces glycosuria ; while the experiments 

 of Claude Bernard and Eckhard show that, after such resection, 

 puncture of the fourth ventricle is not followed by glycosuria. In 

 the case of puncture of the fourth ventricle, irritation of the sugar 

 centre in the medulla is conveyed by way of the sympathetic 

 (splanchnic nerve) to the liver, where it excites that organ to part 

 with its glycogen. Resection of the splanchnic nerve breaks the 

 communication between the centre and the sugar-forming organ, 



