Testosterone and progesterone, but not estradiol, stimulate muscle protein synthesis in postmenopausal women.
Level 2 - randomized trial
Randomized controlled trial evaluating hormone interventions in postmenopausal women with a cross-sectional comparison group.
PubMed 24203065 · doi:10.1210/jc.2013-2835
What was done
Researchers measured the basal muscle protein fractional synthesis rate and skeletal muscle gene expression of growth-regulatory factors (MYOD1, MSTN, FST, FOXO3) in 12 healthy premenopausal women and 24 postmenopausal women matched for body mass, body composition, and insulin sensitivity. Postmenopausal women were studied before and after assignment to one of four parallel groups: testosterone, estradiol, progesterone, or no intervention (control).
What was found
Basal muscle protein fractional synthesis rate was approximately 20% faster, and MYOD1, FST, and FOXO3 mRNA expressions were approximately 40%-90% greater in postmenopausal compared to premenopausal women (all P < .05). In postmenopausal women, both testosterone and progesterone treatment increased muscle protein fractional synthesis rate by approximately 50% (both P < .01), whereas estradiol and control showed no change. Progesterone treatment increased MYOD1 mRNA expression (P < .05) without altering MSTN, FST, or FOXO3. Testosterone and estradiol treatments had no effect on MYOD1, MSTN, FST, or FOXO3 expression.
Why it matters
This study shows that testosterone and progesterone, but not estradiol, stimulate acute muscle protein synthesis in postmenopausal women. It suggests that age-related differences in female muscle protein turnover are not driven by menopause-related changes in circulating estradiol.
Limits
The total sample size was small (n=36 overall; n=6 per postmenopausal arm). The abstract does not disclose the specific doses, routes of administration, or treatment durations used, nor did it measure muscle protein breakdown or longitudinal functional outcomes.
Cited by
- contradicts During menopause, a decline in sex hormones impairs protein synthesis and shifts the body into a catabolic state.