Sex differences in insulin regulation of skeletal muscle glycogen synthase and changes during weight loss and exercise in adults
Authors' conclusion
Sex differences in insulin sensitivity may be explained at the cellular muscle level, and to improve skeletal muscle insulin action in older adults, it may be necessary to recommend different behavioral strategies depending on the individual's sex.
Study context
- Population
- Older men and women; body composition, VO2max and insulin sensitivity (M) by 3-hour hyperinsulinemic-euglycemic clamp with vastus lateralis muscle biopsies60 in interventions
- Participants
- 73 men
- Comparison
- Women vs men; 6-month weight loss or aerobic exercise training
- Outcome
- Sex differences in muscle metabolism at baseline
Main finding
As reported in the abstract
- Women had lower body weight, VO2max and fat-free mass than men
- Men had lower M, lower change (insulin minus basal) in muscle glycogen synthase (GS) activity and lower change in AKT protein expression than women
- M was associated with the change (insulin-basal) in GS activity and the change in AKT protein expression
Further findings
Postintervention minus preintervention change (insulin-basal) (∆∆) in GS activity · 6 months
- Weight loss: ∆∆ in GS activity (fractional, independent, total) higher in men than women
- Aerobic exercise (3×/week): ∆∆ in GS fractional activity higher in women than men
- All participants: ∆∆ in GS fractional and independent activities related to ∆∆ in AKT expression and glycogen content
- n = 60
Original publication
Sex differences in insulin regulation of skeletal muscle glycogen synthase and changes during weight loss and exercise in adults. Obesity (Silver Spring). Published 27 February 2024. doi:10.
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