Studies on the existence of a pathway in liver and muscle for the conversion of glucose into glycogen without glucose 6-phosphate as an intermediate.
Mixtures of (14)C-labelled glucose plus pyruvate were incubated either with rat diaphragm or slices of rat liver. Incorporation of glucose carbon into glycogen was compared with its incorporation into glucose 6-phosphate relative to the incorporation of pyruvate carbon into these metabolic products. There was no preferential incorporation of glucose carbon relative to pyruvate carbon into glycogen compared with glucose 6-phosphate in the liver slices, but there was in diaphragm. On the assumption that glucose 6-phosphate is a necessary intermediate in the conversion of pyruvate carbon into glycogen, this is evidence for the existence in muscle, but not in liver, of more than one pool of glucose 6-phosphate or of a pathway from glucose to glycogen without glucose 6-phosphate as an intermediate. Galactose carbon, relative to pyruvate carbon, was preferentially incorporated into liver glycogen, so that a substrate converted in liver into glycogen without glucose 6-phosphate as an intermediate could be detected by this approach.
D000818:Animals; D002247:Carbon Isotopes; D003964:Diaphragm / Q000378:metabolism; D005690:Galactose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D006003:Glycogen / Q000096:biosynthesis*; D006600:Hexosephosphates / Q000378:metabolism*; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D008112:Liver Glycogen / Q000096:biosynthesis; D009132:Muscles / Q000378:metabolism*; D011773:Pyruvates / Q000378:metabolism; D051381:Rats
D002247:Carbon Isotopes; D006600:Hexosephosphates; D008112:Liver Glycogen; D011773:Pyruvates; D006003:Glycogen; D005947:Glucose; D005690:Galactose