17β-Estradiol Effects in Skeletal Muscle: A 31 P MR Spectroscopic Imaging (MRSI) Study of Young Females during Early Follicular (EF) and Peri-Ovulation (PO) Phases.
Level 4 - case-series / case-control
Small repeated-measures observational study (n=7)
PubMed 38337751 · doi:10.3390/diagnostics14030235
What was done
Seven young females (mean age 28 ± 6 years) underwent 7T phosphorus-31 magnetic resonance spectroscopic imaging (2D 31P FID-MRSI) of the soleus muscle during the early follicular (EF) and peri-ovulation (PO) phases of the menstrual cycle. Circulating 17β-estradiol concentrations were measured alongside muscle phosphoryl metabolites.
What was found
Circulating 17β-estradiol was significantly lower in the EF phase than in the PO phase (28 ± 18 pg/mL vs. 71 ± 30 pg/mL, p < 0.05). ATP-referenced phosphocreatine (PCr) levels were reduced by 5.4 ± 4.3% in the EF phase compared to the PO phase across all subjects. Muscle PCr levels correlated linearly with blood 17β-estradiol levels (r = 0.64, p = 0.014). Inorganic phosphate (Pi) and glycerophosphocholine (GPC) levels did not correlate with 17β-estradiol, though they correlated between EF and PO phases (p = 0.015 for Pi and p = 0.0008 for GPC).
Why it matters
This study provides preliminary in vivo evidence that physiological fluctuations in 17β-estradiol across the menstrual cycle are linked to skeletal muscle high-energy phosphate availability.
Limits
The sample size is extremely small (n = 7). The design is observational and restricted to the soleus muscle. Functional muscle performance, clinical fatigue, and dietary or exercise controls were not reported in the abstract.
Cited by
- context Plasma estradiol levels can increase approximately tenfold from early in the follicular phase to its apex just before ovulation.