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-
- Journal Information:
- J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 26:5; ISSN JNMEA
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
ADENOMAS
ALANINE-ALPHA
ALANINE-L
ALANINES
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BODY
BODY FLUIDS
CARBON 11
CARBON 14 COMPOUNDS
CARBON ISOTOPES
CARBOXYLIC ACIDS
CARCINOMAS
COMPARATIVE EVALUATIONS
COMPUTERIZED TOMOGRAPHY
DIAGNOSIS
DIAGNOSTIC TECHNIQUES
DIAGNOSTIC USES
DIGESTIVE SYSTEM
DISEASES
DISTRIBUTION
DRUGS
EMISSION COMPUTED TOMOGRAPHY
EVEN-ODD NUCLEI
GLANDS
IN VIVO
ISOTOPES
LABELLED COMPOUNDS
LABELLING
LEUCINE
LIGHT NUCLEI
LIVER
MALE GENITALS
MAMMALS
MATERIALS
MINUTES LIVING RADIOISOTOPES
MUSCLES
NEOPLASMS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
POSITRON COMPUTED TOMOGRAPHY
PROSTATE
RADIOACTIVITY
RADIOISOTOPES
RADIOPHARMACEUTICALS
RATS
RODENTS
SUBSTRATES
TISSUE DISTRIBUTION
TOMOGRAPHY
UPTAKE
USES
VERTEBRATES