Labeling of precursor pools for glycosphingolipid biosynthesis. Incorporation of [3H]galactose by rat hepatocytes in primary culture.
UDP-galactose and UDP-glucose are the immediate sources of monosaccharide residues in glycosphingolipid biosynthesis. The incorporation of [6-3H]D-galactose into these compounds was measured in primary cultures of rat hepatocytes, which take up and metabolize galactose rapidly. The UDP-glucose and UDP-galactose content of hepatocytes, determined enzymatically and by the HPLC-analysis of UDP-sugars, was 1.87 +/- 0.22 and 0.51 +/- 0.06 nmol/mg protein, respectively. Galactose concentrations in the medium of up to 7.5 microM did not influence the intracellular levels of UDP-glucose and UDP-galactose. Although the specific radioactivity of these precursor pools did not reach a constant plateau, conditions were defined that allow the calculation of rates of glycolipid synthesis from added labeled galactose. They include the replacement of glucose in the culture medium by sodium pyruvate and D-galactose.
Mesarić
M
M
Biochemisches Institut, Universität Freiburg.
Decker
K
K
D000818:Animals; D002478:Cells, Cultured; D005260:Female; D006028:Glycosphingolipids / Q000096:biosynthesis*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D011773:Pyruvates / Q000378:metabolism; D019289:Pyruvic Acid; D051381:Rats; D011919:Rats, Inbred Strains; D014531:Uridine Diphosphate Galactose / Q000378:metabolism; D014532:Uridine Diphosphate Glucose / Q000378:metabolism
D006028:Glycosphingolipids; D011773:Pyruvates; D014531:Uridine Diphosphate Galactose; D019289:Pyruvic Acid; D014532:Uridine Diphosphate Glucose