Hormone replacement therapy improves contractile function and myonuclear organization of single muscle fibres from postmenopausal monozygotic female twin pairs.

Ageing is associated with a decline in muscle mass and strength leading to increased physical dependency in old age. Postmenopausal women experience a greater decline than men of similar age in parallel with the decrease in female sex steroid hormone production. We recruited six monozygous female twin pairs (55-59 years old) where only one twin pair was on hormone replacement therapy (HRT use = 7.

Hormone therapy is associated with better body composition and adipokine/glucose profiles: a study with monozygotic co-twin control design.

Objective: The aim of this study was to evaluate the possibility of preventing the metabolic health consequences of postmenopausal hypogonadism with the use of long-term hormone therapy (HT).

Methods: We used a monozygotic co-twin control design including 10 twin pairs (aged 56-62 y) discordant for HT (duration of HT, 2-10 y). In addition, 14 premenopausal women (aged 29-35 y) who did not use HT were studied to evaluate the differences in metabolic health between the premenopausal and postmenopausal states.

Muscle function in monozygotic female twin pairs discordant for hormone replacement therapy.

Introduction: Postmenopausal monozygotic twin pairs discordant for hormone replacement therapy (HRT) provide an advantageous study design controlling for genetic background for elucidating the relationships between aging, sex hormone levels, muscle strength, contractile capacity, and fatigability.

Methods: Thirteen postmenopausal monozygotic twin pairs discordant for HRT were measured for maximal voluntary torque (MVC) and twitch characteristics using electrical stimulation before and after intermittent dynamic plantarflexor exercise until exhaustion.

Results: Peak twitch torque was 32% higher in HRT users than in their non-HRT, genetically identical sisters (P = 0.

Age and estrogen-based hormone therapy affect systemic and local IL-6 and IGF-1 pathways in women.

A thorough understanding of the role of estrogens on aging-related muscle weakness is lacking. To clarify the molecular mechanisms underlying the effects of hormone replacement therapy (HRT) on skeletal muscle, we analyzed systemic protein and local mRNA levels of factors related to interleukin 6 (IL-6) and insulin-like growth factor 1 (IGF-1) pathways in 30- to 35-year-old (n = 14) women (without hormonal contraceptives) and in 54- to 62-year-old monozygotic female twin pairs discordant for HRT (n = 11 pairs, mean duration of HRT 7.3 ± 3.

Differential influence of peripheral and systemic sex steroids on skeletal muscle quality in pre- and postmenopausal women.

Aging is associated with gradual decline of skeletal muscle strength and mass often leading to diminished muscle quality. This phenomenon is known as sarcopenia and affects about 30% of the over 60-year-old population. Androgens act as anabolic agents regulating muscle mass and improving muscle performance.