PATHOLOGICAL METABOLISM OF DIABETES 275 



Cause of the Impaired Glucose Utilization in Diabetes 



The relationship between the diabetic defect and the pancreas appears 

 to be definitely established. 



Islet Theory : .Morphologically the pancreas may be regarded as stroma 

 ducts, acini and islands of Langerhans. It has been proposed, notably 

 by Opie in this country, that the antidiabetic internal secretion of the 

 pancreas is elaborated by islet cells. This view finds support in the fol- 

 lowing facts: (1) In diabetes mellitus the islets are frequently found 

 in a state of hydropic or hyaline degeneration, while the remaining organ 

 may appear normal. (2) Cancer, pancreatitis and the experimental injec- 

 tion of caustics into the ducts very frequently spare the islets and fail to 

 cause diabetes. (3) It is claimed that in pancreatic grafts, such as de- 

 scribed above, islet cells predominate, while acinus cells and ducts disap- 

 pear. Grafts of this kind consist of much connective tissue, generally more 

 or less infiltrated with round cells, and collections of epithelium. Con- 

 cerning the latter, remains of ducts and acini are usually present in some 

 proportion and there are also epithelial cell masses regarded as islets 

 on morphological grounds. Differences of opinion still exist as to the 

 relative proportion of the different epithelial elements. Lombroso, whose? 

 exhaustive monograph reviews the literature to 1910, concludes that the 

 internal function of the pancreas is not monopolized by islet cells. Bens- 

 ley developed intravital staining methods which, for the first time, made 

 possible the sure differentiation of the islet cells from duct or acinus 

 epithelium without reference to form or arrangement and appears to have 

 proved that these cells' are regenerated from duct epithelium. He also 

 showed the great normal variations in size and number of islets in differ- 

 ent individuals (guinea-pigs). His study explains certain of the discrep- 

 ancies which occur in the literature, especially in the estimation of the 

 quantity of islet tissue in pancreatic rests, grafts, etc. Allen has re- 

 ported that when proper sized fragments of pancreas in connection with 

 the ducts are left in situ, and the remainder of the gland is removed, the 

 subsequent development of severe diabetes may be coincident with disap- 

 pearance of islet tissue while acinus cells and ducts are unaffected. This 

 operation, according to Allen, is eminently satisfactory for producing 

 experimental diabetes without infection and without loss of the external 

 secretions. 



In completely depancreatized dogs Minkowski saw quantitative ex- 

 cretions of administered carbohydrates and D : N ratios of 2.8 to 1. 



The lower ratios observed in pancreas diabetes as compared with 

 phloridzin diabetes and some cases of diabetes mellitus might perhaps be 

 interpreted as due to differences in the proportion of fat catabolized. 



