The effect of the progression of vitamin A deficiency on glucose, galactose and mannose incorporation into sugar phosphates and sugar nucleotides in hamster liver.

Abstract

The incorporation of [2-3H]mannose into dolichyl phosphate mannose and glycoproteins is markedly reduced in livers of vitamin A-deficient hamsters. To determine whether vitamin A deficiency selectively alters the level of mannose incorporation into sugar phosphates and sugar nucleotides, we studied the in vivo incorporation of [2-3H]mannose, [5-3H]glucose, and [4,5-3H]galactose into sugar phosphates and sugar nucleotides. Male hamsters fed either a vitamin A-depleted or a retinoic acid-supplemented (3 micrograms/g) diet were used at 4, 6 and 8 wk of age; the animals were killed at various time points after an intraperitoneal injection of the radiolabeled sugar. A two- to threefold increase in the amount of [2-3H]mannose was found in liver of hamsters fed a vitamin A-depleted diet for 4 wk, resulting in enhanced incorporation into mannosyl-phosphate and guanosine diphosphate (GDP) mannose. As deficiency progressed, there was a smaller increase in [2-3H]mannose and a significant decrease in [3H]mannose-phosphate and GDP-[3H]mannose, suggesting a decreased mannose kinase activity. [5-3H]Glucose-labeled livers showed no difference in the total uptake of the label or its incorporation into uridine diphosphate glucose and galactose-phosphate during the 8-wk study. However, the synthesis of glucosyl-phosphate was reduced by 50 to 90% at 6 and 8 wk of deficiency, suggesting an impaired gluco-kinase activity. In hamsters injected with [4,5-3H]galactose only [3H]glucose was found within 5 min in the free sugar fraction. In contrast, as much as 70% of the label in the sugar phosphate and sugar nucleotide fraction remained as [3H]galactose even at 60 min. These effects on sugar, sugar phosphate and sugar nucleotide formation in part may explain the effects of vitamin A deficiency on glycoconjugate biosynthesis.

• Authors: S Shankar, K E Creek, L M De Luca
• Journal: The Journal of nutrition (J Nutr) Vol. 120 Issue 4 Pg. 361-74 (Apr 1990) ISSN: 0022-3166 [Print] United States
• PMID: 1691776 (Publication Type: Journal Article)

Chemical References

• Nucleoside Diphosphate Sugars
• Sugar Phosphates
• Guanosine Diphosphate Mannose
• Tretinoin
• Glucose
• Mannose
• Uridine Diphosphate Glucose
• Galactose

Topics

• Animals
• Cricetinae
• Diet
• Galactose (administration & dosage, analysis, metabolism)
• Glucose (administration & dosage, analysis, metabolism)
• Guanosine Diphosphate Mannose (biosynthesis)
• Liver (analysis, drug effects, metabolism)
• Male
• Mannose (administration & dosage, analysis, metabolism)
• Mesocricetus
• Models, Biological
• Nucleoside Diphosphate Sugars (biosynthesis)
• Sugar Phosphates (biosynthesis)
• Time Factors
• Tretinoin (administration & dosage, analysis)
• Uridine Diphosphate Glucose (biosynthesis)
• Vitamin A Deficiency (metabolism)