Metabolic fate of the carboxyl-carbon of valine

Conference · Sun Jan 01 04:00:00 EST 1984 · J. Nucl. Med.; (United States)

OSTI ID:6844037

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

Although several C-11-carboxyl-labeled amino acids show promise for clinical use, few detailed biokinetic studies have been reported. Such information is necessary for the calculation of comprehensive radiation absorbed doses and may reveal additional clinical uses. The authors have collected data in mice at intervals between 1 and 90 m after i.v. injection of D,L-, L-, or D-valine for 22 whole organs or tissue samples and for CO/sub 2/ and urinary excretion. The enantiomers were cleanly separated by HPLC, but studies with the D,L- mixture were also done as additional assurance of purity for the separation (i.e., (D+L)/2=D,L). Elimination of C-11 from L-valine is restricted to the approx. =25% of injected activity (IA) observed as exhaled CO/sub 2/, the production of which appears completed in approx. =15 m, the exhalation in approx. =100m. The remaining 75% IA is available for incorporation directly into proteins or into coenzyme-A after deamination to 2-oxoisovalerate. The approx. =25% IA from D-valine that appears to be retained in the body probably is not converted to L-valine since virtually no CO/sub 2/ is recovered. The pancreatic content of approx. =8% of retained activity (RA) for both L- and D- valine at 90 m suggests similar localization mechanisms for the activity remaining in the body after excretion is ended. A similar correspondence of RA is seen in most other organs, the notable exceptions being the approx. =2 to 3 times higher %RA in blood and muscle for D-valine and in small intestine for L-valine. Studies such as this offer the possibility for quantitation of isolated metabolic processes, in this case production of CO/sub 2/ from 2-oxoisovalerate formed by deamination, and for separating metabolized from non-metabolized localization of C-11 when the D-amino acid can be shown to remain undegraded.

• Research Organization: The Univ. of Chicago, Chicago, IL
• OSTI ID: 6844037
• Report Number(s): CONF-840619-
• Conference Information: Journal Name: J. Nucl. Med.; (United States) Journal Volume: 25:5
• 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
BIOLOGICAL LOCALIZATION
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BLOOD
BODY
BODY FLUIDS
CARBON 11
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON ISOTOPES
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHROMATOGRAPHY
CLEARANCE
COUNTING TECHNIQUES
DIAGNOSTIC USES
DIGESTIVE SYSTEM
DOSES
ENDOCRINE GLANDS
EVEN-ODD NUCLEI
EXCRETION
EXHALATION
GASTROINTESTINAL TRACT
GLANDS
INJECTION
INTAKE
INTESTINES
INTRAVENOUS INJECTION
ISOTOPE APPLICATIONS
ISOTOPES
LABELLING
LIGHT NUCLEI
LIQUID COLUMN CHROMATOGRAPHY
MAMMALS
MATERIALS
METABOLISM
MICE
MINUTES LIVING RADIOISOTOPES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
OXIDES
OXYGEN COMPOUNDS
PANCREAS
RADIATION DOSES
RADIOISOTOPE SCANNING
RADIOISOTOPES
RODENTS
SEPARATION PROCESSES
SKELETON
SMALL INTESTINE
TRACER TECHNIQUES
URINE
USES
VALINE
VERTEBRATES
WASTES