Full resolution (JPEG) - On this page / på denna sida - VII. The Liver - Glycogen and its Formation
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
FORMATION OF GLYCOGEN. 395
in the strictest sense of the word. The knowledge of these last-mentioned
bodies is of the greatest importance in the question as to the origin of
glycogen in the animal body, and the chief interest attaches to the
question: To what extent are the two chief groups of food, the proteins
and carbohydrates, glycogen-formers?
The great importance of the carbohydrates in the formation of gly-
cogen has given rise to the opinion that the glycogen in the liver is pro-
duced from sugar by a synthesis in which water separates with the for-
mation of an anhydride (Luchsinger and others). This theory (anhy-
dride theory) has found opponents because it neither explains the forma-
tion of glycogen from such bodies as proteins, carbohydrates, gelatin,
and others, nor the circumstance that the glycogen is always the same,
independent of the properties of the carbohydrate introduced, whether
it is dextrogyrate or levogyrate. This last circumstance does not now
present any special difficulty, since we know that the simple sugars can
easily be transformed into each other. It was formerly the opinion of
many investigators that all glycogen is formed from protein, and that
this splits into two parts, one containing nitrogen and the other being
free from nitrogen; the latter is the glycogen. According to these
views, the carbohydrates act only in that they spare the protein and
the glycogen produced therefrom (sparing theory of Weiss, Wolffberg,
and others 1
).
In opposition to this theory C. and E. Voit and their pupils have
shown that the carbohydrates are " true " glycogen-formers. After par-
taking of large quantities of carbohydrates, the amount of glycogen stored
up in the body is sometimes so great that it cannot be covered by the
protein? decomposed during the same time, and in these cases a gly-
cogen formation from the carbohydrates must be admitted. According
to Cremer only the fermentable sugars of the six carbon series or their
di- and polysaccharides are true glycogen-formers. For the present, only
glucose, fructose, and to a much less degree galactose (Weinland 2
),
and perhaps also e?-mannose (Cremer) are designated as true glycogen-
formers. Other monosaccharides may indeed, according to Cremer,
influence the formation of glycogen, but they are not converted into
glycogen, and hence are called only pseudoglycogen-formers.
The poly- and disaccharides may, after a cleavage into the cor-
responding fermentable monosaccharides, serve as glycogen-formers.
This is true for at least cane-sugar and milk-sugar, which must first
1
In regard to these two theories, see especially Wolffberg, Zeitschr. f . Biologie, 16.
1
E. Voit, Zeitschr. f. Biologie, 25, 543, and C. Voit, ibid., 2S. See also Kausch
and Socin, Arch. f. exp. Path. u. Pharm., 31; Weinland, Zeitschr. f. Biologie, 40 and
38; Cremer, ibid., 42, and Ergebnisse der Physiol., 1.
<< prev. page << föreg. sida << >> nästa sida >> next page >>
