Accumulation of D- vs. L-isomers of alanine and leucine in rat prostatic adenocarcinoma
It has been reported that tumor tissue may accumulate some D-amino acids preferentially over the L-isomers. In order to investigate the potential use of carbon-11 labeled amino acid isomers for in vivo tumor studies with positron emission tomography in patients, the tissue distributions of alanine and leucine, substrates for the A-type and L-type amino acid transport systems, respectively, were studied in Copenhagen rates bearing the Dunning R3327G prostatic adenocarcinoma. The authors have previously reported differences in the accumulation of A-type vs. L-type amino acids in rat prostatic adenocarcinoma and normal tissues. All compounds were labeled with C-14 in the carboxyl position with specific activities of 30.0-56.6 mCi/mmol. Higher levels of C-14 activity (Relative Concentration (RC)=dpm found per gm tissue + dpm inject per gm animal mass) were observed in tumor tissue using D-alanine (0.71) compared to L- (0.21) or DL-alanine (0.27) at 45 min post-injection. While tumor/prostate and tumor/liver ratios were above 2 for all three substrates, tumor/blood and tumor/muscle were above one for only the D-isomer. Comparisons made with D-, L-, and DL-leucine also demonstrated a higher level of RC in tumor tissue with the D-isomer (0.84) vs. the L-(0.66) and DL-leucine (0.63). In this case, however, tumor/blood, tumor/prostate, and tumor/muscle ratios were above one for all three substrates, while tumor/liver ratios were below one. These results support the observation of a preferential accumulation of D-amino acids in tumor tissue over the natural L-isomers. Observed differences in the accumulation of the isomers in normal tissues are discussed.
- Research Organization:
- Memorial Sloan-Kettering Cancer Center, New York, NY 10021
- OSTI ID:
- 6853465
- Report Number(s):
- CONF-850611-; TRN: 87-010917
- Journal Information:
- J. Nucl. Med.; (United States), Vol. 26:5; Conference: 32. annual meeting of the Society of Nuclear Medicine, Houston, TX, USA, 2 Jun 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ADENOMAS
DIAGNOSIS
ALANINE-L
DIAGNOSTIC USES
LABELLING
TISSUE DISTRIBUTION
UPTAKE
CARCINOMAS
LEUCINE
PROSTATE
POSITRON COMPUTED TOMOGRAPHY
BLOOD
CARBON 11
CARBON 14 COMPOUNDS
COMPARATIVE EVALUATIONS
IN VIVO
LIVER
MUSCLES
RADIOACTIVITY
RADIOPHARMACEUTICALS
RATS
SUBSTRATES
ALANINE-ALPHA
ALANINES
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BODY
BODY FLUIDS
CARBON ISOTOPES
CARBOXYLIC ACIDS
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
DIGESTIVE SYSTEM
DISEASES
DISTRIBUTION
DRUGS
EMISSION COMPUTED TOMOGRAPHY
EVEN-ODD NUCLEI
GLANDS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
MALE GENITALS
MAMMALS
MATERIALS
MINUTES LIVING RADIOISOTOPES
NEOPLASMS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RADIOISOTOPES
RODENTS
TOMOGRAPHY
USES
VERTEBRATES
550602* - Medicine- External Radiation in Diagnostics- (1980-)