43O INTERNAL SECRETION 



the pancreas and stimulated by the adrenal system. What \ve 

 know concerning the site of the activity of adrenalin suggests 

 that the pancreatic hormone has an inhibitory action upon the 

 nervous apparatus which regulates the formation of sugar. Lowi's 

 reaction also points to an inhibitory action, on the part of the 

 pancreas, upon organs with sympathetic innervation. 



The investigations of Eppinger, Falta and Rudinger, to 

 which frequent reference has been made, show that a certain in- 

 fluence is exercised by the thyroid apparatus upon the metabolism 

 of the carbohydrates, and that this influence is apparently brought 

 into play by the agency of the pancreas. The results of their 

 experiments seem to show that, while the activity of the thyroid 

 is opposed to the internal secretory activity of the pancreas, that 

 of the parathyroids is favourable to it. The assumption is that 

 the thyroid hormone stimulates the function of the vegetative 

 nervous system ; and that the pancreatic hormone affects that 

 function in the opposite sense. 



From the data which have here been set forth, we are justified 

 in concluding that the pancreas, by means of its internal secretion, 

 inhibits the formation of sugar in the liver, and that this inhibition 

 is effected through the agency of certain nervous apparatuses. 

 Suppression of pancreatic activity abolishes the normal check 

 upon the formation of sugar, in consequence of which the glyco- 

 gen present in the organism is released ; that is to say, the 

 glycogen derived from the carbohydrates in the food or, in de- 

 fault of these, from other material, is converted into glucose ; and 

 as a consequence hyperglycasmia and glycosuria follow. The 

 pancreatic hormone appears to affect the same peripheral nervous 

 apparatus as adrenalin ; for, as Kaufmann showed, resection of 

 the splanchnic nerve is followed by pancreatic diabetes in exactly 

 the same manner as adrenalin glycosuria. 



Attempts to isolate the pancreatic hormone have, up to now, 

 been fruitless. Nothing definite is known concerning its chemical 

 nature and we are forced to fall back upon hypothesis. The most 

 probable assumption is, that the substance is of the nature of a 

 ferment, and that it influences that process by which the decom- 

 position and new formation of glycogen take place in the liver. 

 The fact that, after extirpation of the pancreas, deposition of 

 glycogen in the liver may be effected by the administration of 

 levulose, suggests that suppression of the pancreatic function 

 does not prevent the formation of glycogen, but that it permits 

 the unchecked splitting up of this substance. The normal pan- 

 creatic hormone is a substance which inhibits the diastatic con- 

 version of glycogen into sugar. 



Many experiments have been undertaken with the object of 

 discovering the path along which the pancreatic hormone travels, 

 and the results were described by me in 1898. I discovered that 

 in the large majority of instances (66 to 86 per cent.), ligature 



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