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  1. Artikel ; Online: Lifespan Effects of Muscle-Specific Androgen Receptor Overexpression on Body Composition of Male and Female Rats.

    Barsky, Sabrina Tzivia / Monks, Douglas Ashley

    Endocrinology

    2024  Band 165, Heft 3

    Abstract: Androgenic actions of gonadal testosterone are thought to be a major mechanism promoting sex differences in body composition across the lifespan. However, this inference is based on studies of androgen receptor (AR) function in late adolescent or ... ...

    Abstract Androgenic actions of gonadal testosterone are thought to be a major mechanism promoting sex differences in body composition across the lifespan. However, this inference is based on studies of androgen receptor (AR) function in late adolescent or emerging adult rodents. Here we assess body composition and AR expression in skeletal muscle of rats at defined ages, comparing wild-type (WT) to transgenic human skeletal actin-driven AR overexpression (HSAAR) rats which overexpress AR in skeletal muscle. Male and female HSAAR and WT Sprague Dawley rats (N = 288) underwent dual-energy x-ray absorptiometry (DXA) scanning and tissue collection at postnatal day (PND) 1, 10, 21, 42, 70, 183, 243, and 365. Expected sex differences in body composition and muscle mass largely onset with puberty (PND-21), with no associated changes to skeletal muscle AR protein. In adulthood, HSAAR increased tibialis anterior (TA) and extensor digitorum longus mass in males, and reduced the expected gain in gonadal fat mass in both sexes. In WT rats, AR protein was reduced in soleus, but not TA, throughout life. Nonetheless, soleus AR protein expression was greater in male rats than female rats at all ages of sexual development, yet only at PND-70 in TA. Overall, despite muscle AR overexpression effects, results are inconsistent with major sex differences in body composition during sexual development being driven by changes in muscle AR, rather suggesting that changes in ligand promote sexual differentiation of body composition during pubertal timing. Nonetheless, increased skeletal muscle AR in adulthood can be sufficient to increase muscle mass in males, and reduce adipose in both sexes.
    Mesh-Begriff(e) Rats ; Animals ; Female ; Male ; Humans ; Adolescent ; Receptors, Androgen/metabolism ; Longevity ; Rats, Sprague-Dawley ; Androgens/metabolism ; Muscle, Skeletal/metabolism ; Body Composition/genetics
    Chemische Substanzen Receptors, Androgen ; Androgens
    Sprache Englisch
    Erscheinungsdatum 2024-02-01
    Erscheinungsland United States
    Dokumenttyp Journal Article
    ZDB-ID 427856-2
    ISSN 1945-7170 ; 0013-7227
    ISSN (online) 1945-7170
    ISSN 0013-7227
    DOI 10.1210/endocr/bqae012
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  2. Artikel ; Online: Androgen action on myogenesis throughout the lifespan; comparison with neurogenesis.

    Barsky, Sabrina Tzivia / Monks, Douglas Ashley

    Frontiers in neuroendocrinology

    2023  Band 71, Seite(n) 101101

    Abstract: Androgens' pleiotropic actions in promoting sex differences present not only a challenge to providing a comprehensive account of their function, but also an opportunity to gain insights by comparing androgenic actions across organ systems. Although often ...

    Abstract Androgens' pleiotropic actions in promoting sex differences present not only a challenge to providing a comprehensive account of their function, but also an opportunity to gain insights by comparing androgenic actions across organ systems. Although often overlooked by neuroscientists, skeletal muscle is another androgen-responsive organ system which shares with the nervous system properties of electrochemical excitability, behavioral relevance, and remarkable capacity for adaptive plasticity. Here we review androgenic regulation of mitogenic plasticity in skeletal muscle with the goal of identifying areas of interest to those researching androgenic mechanisms mediating sexual differentiation of neurogenesis. We use an organizational-activational framework to relate broad areas of similarity and difference between androgen effects on mitogenesis in muscle and brain throughout the lifespan, from early organogenesis, through pubertal organization, adult activation, and aging. The focus of the review is androgenic regulation of muscle-specific stem cells (satellite cells), which share with neural stem cells essential functions in development, plasticity, and repair, albeit with distinct, muscle-specific features. Also considered are areas of paracrine and endocrine interaction between androgen action on muscle and nervous system, including mediation of neural plasticity of innervating and distal neural populations by muscle-produced trophic factors.
    Mesh-Begriff(e) Female ; Male ; Humans ; Androgens ; Receptors, Androgen/physiology ; Longevity ; Neurogenesis ; Muscle, Skeletal ; Muscle Development
    Chemische Substanzen Androgens ; Receptors, Androgen
    Sprache Englisch
    Erscheinungsdatum 2023-09-03
    Erscheinungsland United States
    Dokumenttyp Journal Article ; Review
    ZDB-ID 390985-2
    ISSN 1095-6808 ; 0532-7466 ; 0091-3022
    ISSN (online) 1095-6808
    ISSN 0532-7466 ; 0091-3022
    DOI 10.1016/j.yfrne.2023.101101
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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    Verfügbar in ZB MED Köln/Königswinter

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  3. Artikel ; Online: Myocytic androgen receptor overexpression does not affect sex differences in adaptation to chronic endurance exercise.

    Barsky, Sabrina Tzivia / Monks, Douglas Ashley

    Biology of sex differences

    2022  Band 13, Heft 1, Seite(n) 59

    Abstract: Muscle-specific androgen receptor (AR) overexpression (HSAAR transgene) in sedentary male rats results in reduced adiposity, increased mitochondrial enzyme activity, and selective increase in Type 2b myofiber size. Here, we tested chronic endurance ... ...

    Abstract Muscle-specific androgen receptor (AR) overexpression (HSAAR transgene) in sedentary male rats results in reduced adiposity, increased mitochondrial enzyme activity, and selective increase in Type 2b myofiber size. Here, we tested chronic endurance exercise interactions with this phenotype in both sexes. Across 9 weeks, rats ran 5×/week on motorized running wheels at increasing speeds and durations. Exercise reduced fat mass in all groups, but sex affected endurance exercise outcomes such that absolute lean mass increased only in females and total body mass decreased only in males. Expected sex differences were observed with males exhibiting greater total body and lean mass; absolute and relative fat mass; bone mineral density; extensor digitorum longus (EDL) myofiber size and glycolytic proportion; but lesser Type 2a and Type 1 myosin expression in tibialis anterior. Observed HSAAR outcomes were not altered by sex, with transgenic rats having greater lean mass, Type 2a myosin expression in soleus, and glycolytic myofiber size in EDL. Tibialis AR content was independently affected by sex, HSAAR, and exercise. No sex differences were observed in tibialis AR expression in wild-type rats, although HSAAR males had greater AR content than HSAAR females. We identified a moderate correlation between AR expression and glycolytic myofiber size, but not whole-body composition. Overall, results suggest myocytic AR overexpression and chronic exercise, despite sharing a similar phenotype to adaptation, are mediated by distinct mechanisms. Further, this study illustrates sex differences in adaptation to chronic endurance exercise, and suggests sex-similarity in the relationship between muscle AR and exercise response.
    Mesh-Begriff(e) Female ; Rats ; Male ; Animals ; Physical Conditioning, Animal/physiology ; Receptors, Androgen/metabolism ; Muscle, Skeletal/physiology ; Body Composition
    Chemische Substanzen Receptors, Androgen
    Sprache Englisch
    Erscheinungsdatum 2022-10-23
    Erscheinungsland England
    Dokumenttyp Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2587352-0
    ISSN 2042-6410 ; 2042-6410
    ISSN (online) 2042-6410
    ISSN 2042-6410
    DOI 10.1186/s13293-022-00471-x
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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