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ORIGIN OF THE SUGAR. 409
due to synthesis, where a disaccharide is formed. According to J. de
Mkyku neither the pancreas nor the tissues as a whole contain any
glycolytic enzymes. According to him only the blood has a glycolytic
action, and this action is supported by a body acting as an amboceptor
and produced in the pancreas. Our knowledge as to the existence of the
glycolysis and the mode of action of the pancreas in the metabolism of
sugar in the animal body is very meager and incomplete.
Where does the sugar eliminated in diabetes originate? Does it
depend entirely upon the carbohydrates of the food or the store of car-
bohydrates in the body, or has the body the power of producing sugar
from other material? To Luthje belongs the credit for positively
deciding this question. He has made experiments on dogs with pan-
creas diabetes, in which on a protein diet free from carbohydrates so much
sugar was eliminated that it could not possibly be accounted for by
the store of glycogen or other carbohydrate-containing substances in the
body. Similar experiments were also performed later by Pfluger,2
with the results that the power of the animal body to produce sugar from
non-carbohydrate material is now definitely proved.
Is this sugar produced from protein or fat, or from both? This ques-
tion so far has not been answered, and it is the subject of continuous
dispute. It is not possible to enter into an exhaustive and detailed
discussion of the question in a text-book, and we will only mention,
briefly, certain of the most important observations and historical points.
The largest amount of sugar which we can obtain theoretically from
protein is 8 grams of sugar from 1 gram of protein nitrogen, if we admit
that all the carbon of the protein, with the exception of that necessary
to form ammonium carbonate, is used for the formation of sugar. These
results are still somewhat too high for the average carbon and nitrogen
content of the proteins and the values D:N = 6.6 is probably more correct.3
The actual relation between glucose and nitrogen in the urine, i.e.,
the quotient D: N, has been repeatedly determined in various forms of
diabetes, and in depancreatized dogs it is generally 2.8 and in starving
dogs or dogs fed with protein and poisoned with phlorhizin it is equal to
3.65 (Lusk). It may undergo considerable variation, and in certain
cases it may indeed be lower than 1 as well as higher than 8, and high
results have been repeatedly obtained in cases of human diabetes. From
these quotients conclusions have been drawn as to the amount of sugar
1
Cited from Centralbl. f. Physiol., 20 and 23. See also Lepine, Etat actuel de la
question de la Glycolyse, La semaine medicale, 1911.
’Luthje, Deutsch. Arch. f. klin. Med., "9, and Pfluger’s Arch., 106; Pfluger, Pflii-
ger’s Arch., 10S.
* See Falta, Zeitschr. f. klin. Med., 65; see also Gigon, Deutsch. Arch. f. klin. Med., 97.
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