654 DIABETES 



unchanged triose in the passages. There was marked diminution of 

 urine with albuminuria, which then persisted for 10 days. A dose 

 of 6.8 gm. per kg. killed in 4 hours. In no case was there an alimentary 

 triosuria. The average lethal dose by the subcutaneous route was 

 2.2 gm. per kg. as compared with 18 gm. of glucose per kg. in the 

 same set of animals. Suppression of urine is a regular manifestation, 

 but the visceral changes at autopsy are slight. When d,l-glyceric 

 aldehyde is injected intravenously at the rate of only 0.15 gm. per kg. 

 per hour, and possibly at slower rates, unchanged glyceric aldehyde 

 appears in the urine, but no glucose. (It will be recalled that glucose 

 may be injected continuously at the rate of 0.8 gm. to 0.9 gm. per kg. 

 per hour without causing glycosuria.) When administered to diabetic 

 individuals d,l-glyceric aldehyde may increase glycosuria. When 

 given to completely phlorhizinized and glycogen-free dogs it is pos- 

 sible to demonstrate a quantitative conversion of the triose into glucose, 

 the increase in glycosuria corresponding exactly with the weight of 

 glyceric aldehyde given. However, owing to the toxic effects of gly- 

 ceric aldehyde on the kidneys there may be an incomplete excretion 

 of all the sugar formed. The suppression of urine has in the past 

 been mistaken for a beneficial effect, since it may lead to diminished 

 excretions of sugar, acetone, aceto-acetic and /3-hydroxybutyric acids. 



Embden and his coworkers demonstrated the formation of lactic 

 acid from glyceric aldehyde added to washed blood corpuscles. The 

 keto-triose, dihydroxyacetone, was observed to produce less lactic acid, 

 but otherwise it is not improbable that the behavior of the ketotriose 

 is analogous to that of the aldo forms. Thus Mostowski found dihy- 

 droxyacetone to be a glycogen former, and Ringer ^^ reported its com- 

 plete transformation into glucose in the fully phlorhizinized dog. 



The complete conversion of d,l-glyceric aldehyde into glucose in 

 phlorhizinized dogs — its transformation into glycogen in the perfused 

 liver, its disappearance as such when added to liver emulsions, all 

 indicate that glyceric aldehyde (like diose and other sugars in general) 

 is converted into glucose in the body as a preliminary stej) in utili- 

 zation. The fact that large doses may be given by the alimentary 

 route without causing melituria or death, whereas much snuiller doses 

 given subcutaneously may prove lethal, together with the verj' low 

 rate at which glyceric aldehyde has to be given by vein in order not to 

 produce melituria, all point to the liver (and bowel wall) as the chief 

 sites of its conversion. Glyceric aldehyde has figured prominently 

 in theories of the normal catabolism of glucose, antl on the basis of his 

 observations concerning the formation of lactic acid from this triose 

 by blood corpuscles Embden regards it as a chief normal intermediate 

 substance in the oxidation of glucose in the cells. Now glucose may 

 be oxidized in the body at the rate of 0.0 gm. per kg. per hour under 

 suitable circumstances, and if every molecule of glucose oxidized were 



» Ringer and Frankel, Jour. Biol. Cheni., 1914 (IS), 233. 



