D-valine as an indicator for metabolic changes in L-valine

Conference · Wed May 01 04:00:00 EDT 1985 · J. Nucl. Med.; (United States)

OSTI ID:7030776

Faulhaber, P; Bartlett, R; Lathrop, K A; Harper, P V

Racemic C-11-carboxyl labeled amino acids are easily prepared and have been proven useful as pancreatic imaging agents in humans. The authors are continuing an investigation of the biokinetics and metabolism of one of these, C-11 labeled valine using the D-enantiomer to measure tissue distribution of ''unchanged'' valine and comparing it to L-valine. Mice were injected IV with D-, L-, or D,L-valine, and data collected for various tissues, exhaled CO/sub 2/ and urine at intervals between 1 and 150 min. The % injected activity (IA) per organ for D-valine was multiplied by the ratio of the % retained activity (RA) for L-valine to % RA for D-valine. This value is assumed to represent ''unchanged'' L-valine; it was subtracted from the measured % IA for L-valine to give metabolized C-11. Greatest differences are an increasing excess of --15% for small intestine (SI) and an increasing deficit of --15% for muscle at 120 min. Muscle is apparently an active site for incorporation of C-11 from L-valine into other molecules which are then concentrated in the SI. Some tissues were homogenized in chloroform-methanol (2:1), mixed with a small amount of water, centrifuged, and the 3 resulting layers assayed for C-11. In the liver, for example, at 15 and 45 min there was no activity in the chloroform layer for D-, or L-valine. The aqueous layer contained 18% sample activity (SA) at 15 min and 10% SA at 45 min for L-valine, and --78% SA at both times for D-valine; the tissue layer contained 82% SA and 91% SA, for L-valine, and --22% SA for D-valine at both times. Use of enantiomers in this way gives the possibility of quantitating isolated metabolic processes.

• Research Organization: The Univ. of Chicago, Chicago, IL
• OSTI ID: 7030776
• Report Number(s): CONF-850611-
• Conference Information: Journal Name: J. Nucl. Med.; (United States) Journal Volume: 26:5
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY
BODY FLUIDS
CARBON 11
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON ISOTOPES
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTION YIELD
COUNTING TECHNIQUES
DIAGNOSTIC USES
DIGESTIVE SYSTEM
DISTRIBUTION
DRUGS
ENANTIOMORPHS
ENDOCRINE GLANDS
EVEN-ODD NUCLEI
GASTROINTESTINAL TRACT
GLANDS
INJECTION
INTAKE
INTESTINES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LABELLING
LIGHT NUCLEI
LIVER
MAMMALS
MAN
MATERIALS
METABOLISM
MICE
MINUTES LIVING RADIOISOTOPES
MUSCLES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
OXIDES
OXYGEN COMPOUNDS
PANCREAS
PRIMATES
RADIOISOTOPE SCANNING
RADIOISOTOPES
RADIOPHARMACEUTICALS
REACTION KINETICS
RODENTS
SMALL INTESTINE
SYNTHESIS
TIME DEPENDENCE
TRACER TECHNIQUES
UPTAKE
URINE
USES
VALINE
VERTEBRATES
WASTES
YIELDS