l'lll.nh'l////\ DIAHKTI.s 663 



jc'cted to some treatnuMit wliii-h has a strong- j^lycogen niohili/iiij,' ef- 

 fect the glycosuria may be made to rise temporarily, just as though 

 the dog had been given a dose of sugar. Thus, exposure to cold suf- 

 ficient to cause shiverinji:, the administration of ('i)iiu'phrinc. or an 

 ether or nitrous oxide narcosis, injection of acid (and various other 

 toxic substances capable of producing tissue asphyxia and acidosis), all 

 may increase the urinary glucose without increasing the nitrogen, and 

 thus cause an increased G :N ratio. P>ut if the exposure to cold is 

 long and intense enough a time conies when it ceases to have this ett'ect, 

 and if epinephrine is given subcutaneously in the dosage of about 0.4 

 mg. per kg. of body weight once ever}- three hours there is for a tinie 

 a heavy increase of the glucose output, but this becomes less and less 

 until after 6 or 8 doses the ratio becomes constant again, regardless of 

 whether epincj)hrine is given or not. In such dogs neither cold nor 

 narcosis nor other toxic effects will increase the output of glucose, 

 and analyses of the liver and muscles reveal no glycogen. In a long 

 series of dogs so treated Sansum and the writer have not encountered 

 ratios above 3.2 to 1, and the 2.8 ratio recurs frequently. 



Since the glycogen is gone and the dog is fasting, the sugar which 

 continues to appear in the urine must have its origin in body fat or 

 protein, or both. 



Sugar from Fat. — If such a dog be given large cpiantities of fat 

 in the diet no change occurs in the G : N ratio, nor any increase in 

 the glycosuria, except such as may be ascribed to the glycerol of the 

 fat (Lusk). On the other hand, propionic acid, according to Ringer, 

 may cause a rise in the sugar excretion and a corresponding rise in 

 the G : N ratio.*^ From this it is concluded that the fats of the food 

 do not as a rule form sugar in the body, although sugar formation 

 from at least one lower fatty acid is possible in view of Ringer's 

 experiment. 



Von Noorden and Falta and their associates have regarded sugar 

 formation from fat as a regular normal ]>henomenon, because in dia- 

 betes melitus they believe that high ratios occur wliich make this 

 view necessary. 



Sugar from Protein. — If instead of fat, ]irotein be given to the 

 dog above mentioned, there occurs an absolute rise in the sugar of 

 the uriiu^ and a corres])onding rise in the nitrogen, hut the G:X 

 ratio remains constant. Following a meat feeding there may be fluc- 

 tuations of the ratio during short periods, but this statement generally 

 holds if the time of observation is 12 to 24 hours. These facts have 

 led to the conclusion that when in a fasting, fully phlorhizinized ani- 

 mal, or one fed on meat and fat alone, a constant (r : X ratio of 3.65 : 1 

 is seen ; this means that the glucose and the nitrogen are coming from 

 one and the same source, viz., protein. A cram of uitrotren corresponds 



*^ The do<rs used l)y Uiiisrer wore not free of glycogen and possibly the extra sugar 

 did not arise from the acid given. 



