# IN VIVO MUSCLE TRANSPORT OF N-13 AND N-11 AMINO ACIDS

> **NIH NIH R01** · MEMORIAL HOSPITAL FOR CANCER & ALLIED DI · 1987 · $97,307

## Abstract

A major component of cancer cachexia is loss of muscle protein.  This
project seeks to evaluate a method to examine muscle wasting in cancer by
quantitative in vivo study of amino acid transport and protein synthesis in
skeletal muscle of human cancer patients using amino acids labeled with the
short-lived, positron-emitting radionuclides N-13 and C-11.  The present
proposal is limited to studies of amino acid transport in skeletal muscle
of two animal models:  (a) fasting in dogs; and (b) cancer (VX2 carcinoma)
in rabbits.

The advantages of N-13 and C-11 as radiolabels are exploited in a
relatively noninvasive technique for quantitative measurement of regional
blood flow and transport.  A true tracer of an amino acid labeled with N-13
and C-11 is coinjected with an intravascular tracer labeled with Tc-99m
into the arterial blood supply of a peripheral muscle region, and the
tracer kinetics are monitored by external gamma ray counting.  Parameters
specifically quantifying capillary and cell membrane transport are derived
from the resulting data.

Nitrogen-13 L-leucine and C-11 Yield-aminoisobutyric acid (a model
substrate for the A, or alanine-preferring, system of amino acid transport)
will be used in the animal models to examine the role of transport in
regulating cellular uptake of branched-chain amino acids and release of
alanine in skeletal muscle in acute and prolonged starvation, and
precachetic and cachetic cancer.  Plasma hormone levels and muscle protein
synthesis rates will also be measured and examined for correlations with
leucine and AlB transport parameters.

## Key facts

- **NIH application ID:** 3177766
- **Project number:** 5R01CA039058-03
- **Recipient organization:** MEMORIAL HOSPITAL FOR CANCER & ALLIED DI
- **Principal Investigator:** Murray Brennan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $97,307
- **Award type:** 5
- **Project period:** 1985-04-01 → 1988-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3177766

## Citation

> US National Institutes of Health, RePORTER application 3177766, IN VIVO MUSCLE TRANSPORT OF N-13 AND N-11 AMINO ACIDS (5R01CA039058-03). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3177766. Licensed CC0.

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