# EFFECT OF AGE ON MUSCLE PROTEIN SYNTHESIS

> **NIH NIH R01** · UNIVERSITY OF ROCHESTER · 1992 · $130,184

## Abstract

DESCRIPTION (Investigator's Abstract):  The long term goal of this project
is to elucidate the biochemical basis of the muscle atrophy that occurs
during aging in humans.  The immediate goal is to test the hypothesis that
the rate of muscle protein synthesis declines with aging in humans.
Studies will be done in fed and fasting subjects to determine if the effect
of age depends on nutritional status.  Both myofibrillar and sarcoplasmic
protein synthesis will be determined.  Muscle protein synthesis will be
correlated with muscle mass strength, and muscle fiber size to determine if
older subjects with the most evidence of a decline in muscle function have
the lowest rates of protein synthesis.  Subjects will be healthy men, both
young (18-30 years old) and old (60-70 years old).  Their quadriceps
strength will be determined by the force of a maximal voluntary
contraction, and their total muscle mass will be estimated from urinary
creatinine excretion on a meat-free diet.  Muscle fiber size and
distribution (type 1 vs type 2) will be determined by histochemical
analysis of a biopsy taken from a quadriceps muscle (vastus lateralis).
Muscle protein synthesis will be determined from the rate of incorporation
of 1-[1-13C] leucine into myofibrillar and sarcoplasmic proteins (obtained
by biopsy of vastus lateralis) during continuous infusion of 1-[1-13C}
leucine.  Plasma enrichment of [13C] alphaketoisocaproate (derived from
intracellular deamination of [13C] leucine) will be used to estimate the
labeling of the pool of leucine used for protein synthesis.  Protein
synthesis also will be calculated using plasma [13C] leucine enrichment and
intracellular free leucine enrichment in muscle as estimates of the
labeling of the pool of leucine used for protein synthesis.  The applicants
suggest that these data will provide a substantial advance in our knowledge
about the effect of age on protein metabolism in humans, which consists
mainly of estimates of whole-body protein turnover.

## Key facts

- **NIH application ID:** 3121762
- **Project number:** 5R01AG009833-02
- **Recipient organization:** UNIVERSITY OF ROCHESTER
- **SAM.gov UEI:** F27KDXZMF9Y8
- **Principal Investigator:** STEPHEN L WELLE
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1992
- **Award amount:** $130,184
- **Award type:** 5
- **Project period:** 1991-09-01 → 1994-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3121762

## Citation

> US National Institutes of Health, RePORTER application 3121762, EFFECT OF AGE ON MUSCLE PROTEIN SYNTHESIS (5R01AG009833-02). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3121762. Licensed CC0.

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