In vivo formation of tritium-labeled lactic acid from (2-/sup 3/H)mannose or (15-/sup 3/H)retinol by hamster intestinal epithelial cells
In studies to reexamine the in vivo occurrence of retinyl phosphate mannose we injected hamsters with either (2-/sup 3/H)mannose or (15-/sup 3/H)retinol. The small intestine was removed, the epithelial cells were scraped, and a methanolic extract of the labeled cells was prepared and chromatographed on a Mono Q anion-exchange column. Intraperitoneal administration of either (2-/sup 3/H)mannose or (15-/sup 3/H)retinol lead to the formation of a tritium-labeled anionic compound with a retention time on the Mono Q column similar to that of standard retinyl phosphate mannose. However, the biochemical properties of this labeled anionic compound were those expected of an organic acid and not retinyl phosphate mannose. The compound was resistant to both strong acid hydrolysis and mild base hydrolysis, as well as digestion with alpha- or beta-mannosidase, phosphodiesterase I, nucleotide pyrophosphatase, or beta-glucuronidase. When chromatographed on an Aminex HPX-87H organic acid analysis column or a silicic acid column the labeled anionic compound derived from either (2-/sup 3/H)mannose or (15-/sup 3/H)retinol comigrated with standard lactic acid. Treatment of the anionic compound derived from (2-/sup 3/H)mannose with lactate oxidase or L-lactate 2-monooxygenase resulted in the formation of a tritium-labeled product that cochromatographed, respectively, with pyruvate or acetate on the Aminex HPX-87H column. However, treatment of the anionic compound derived from (15-/sup 3/H)retinol with these same two enzymes resulted in a labeled product that migrated on the Aminex column at the same position as tritiated water. This result demonstrated that the labeled hydrogen was removed during enzymatic digestion and suggested that it was present on the second carbon of lactic acid. During the course of these studies no evidence for the in vivo labeling of a compound with the properties of retinyl phosphate mannose was found.
- Research Organization:
- National Cancer Institute, Bethesda, MD
- OSTI ID:
- 6501574
- Journal Information:
- Arch. Biochem. Biophys.; (United States), Vol. 2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LACTATES
BIOCHEMICAL REACTION KINETICS
MANNOSE
VITAMIN A
CHROMATOGRAPHY
EPITHELIUM
HAMSTERS
HYDROLYSIS
IN VIVO
INTESTINES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ALDEHYDES
ANIMAL TISSUES
ANIMALS
BODY
CARBOHYDRATES
CARBOXYLIC ACID SALTS
CHEMICAL REACTIONS
DECOMPOSITION
DIGESTIVE SYSTEM
GASTROINTESTINAL TRACT
HEXOSES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LYSIS
MAMMALS
MONOSACCHARIDES
ORGANIC COMPOUNDS
ORGANS
REACTION KINETICS
RODENTS
SACCHARIDES
SEPARATION PROCESSES
SOLVOLYSIS
TISSUES
VERTEBRATES
VITAMINS
550201* - Biochemistry- Tracer Techniques