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Myocyte androgen receptors increase metabolic rate and improve body composition by reducing fat mass.

ABSTRACT: Testosterone and other androgens are thought to increase lean body mass and reduce fat body mass in men by activating the androgen receptor. However, the clinical potential of androgens for improving body composition is hampered by our limited understanding of the tissues and cells that promote such changes. Here we show that selective overexpression of androgen receptor in muscle cells (myocytes) of transgenic male rats both increases lean mass percentage and reduces fat mass. Similar changes in body composition are observed in human skeletal actin promoter driving expression of androgen receptor (HSA-AR) transgenic mice and result from acute testosterone treatment of transgenic female HSA-AR rats. These shifts in body composition in HSA-AR transgenic male rats are associated with hypertrophy of type IIb myofibers and decreased size of adipocytes. Metabolic analyses of transgenic males show higher activity of mitochondrial enzymes in skeletal muscle and increased O(2) consumption by the rats. These results indicate that androgen signaling in myocytes not only increases muscle mass but also reduces fat body mass, likely via increases in oxidative metabolism.

SUBMITTER: Fernando SM

PROVIDER: S-EPMC2903941 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature

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Myocyte androgen receptors increase metabolic rate and improve body composition by reducing fat mass.

Fernando Shannon M SM Rao Pengcheng P Niel Lee L Chatterjee Diptendu D Stagljar Marijana M Monks D Ashley DA

Endocrinology 20100428 7

Testosterone and other androgens are thought to increase lean body mass and reduce fat body mass in men by activating the androgen receptor. However, the clinical potential of androgens for improving body composition is hampered by our limited understanding of the tissues and cells that promote such changes. Here we show that selective overexpression of androgen receptor in muscle cells (myocytes) of transgenic male rats both increases lean mass percentage and reduces fat mass. Similar changes i ...[more]

PMID: 20427479

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Project description:BackgroundAndrogen deprivation therapy (ADT) has adverse effects on body composition, including muscle wasting and body fat accumulation, which may be attenuated by nutrition therapy. This systematic review summarises available evidence on the effects of dietary interventions on lean mass, fat mass and body mass index (BMI) in men treated with ADT for prostate cancer.MethodsMEDLINE, Embase, Web of Science and ClinicalTrials.org were searched from inception through December 2020. We included all controlled trials evaluating effects of supplementation or dietary interventions on body composition in men with prostate cancer receiving continuous ADT. Methodological quality of the studies was assessed using the Cochrane Collaboration's risk of bias tool. Meta-analysis was performed using a random effects model to calculate standardised mean differences between intervention and comparator groups. (PROSPERO; CRD42020185777).ResultsEleven studies (n = 536 participants) were included. Seven studies investigated the effects of dietary advice interventions, e.g. individual or group counselling, and four studies included a nutritional supplement. Eight studies combined the dietary intervention with exercise. Nine studies reported sufficient data for inclusion in the meta-analysis. Dietary advice and supplementation interventions combined were not associated with significant changes in lean mass (0.05 kg; 95% CI: -0.17, 0.26; p = 0.674; n = 355), fat mass (-0.22 kg; 95% CI: -0.45, 0.01; p = 0.064; n = 336) or BMI (-0.16 kg*m-2; 95% CI: -0.37, 0.04; p = 0.121; n = 399). Dietary advice interventions alone were associated with a significant fat mass reduction (-0.29 kg; 95% CI: -0.54, -0.03; p = 0.028; n = 266).ConclusionsMost studies were dietary advice interventions targeting caloric restriction, which showed the potential to reduce fat mass but did not increase lean mass in men treated with ADT. Future interventions should investigate whether a combination of dietary advice and protein supplementation with concomitant resistance exercise could counteract ADT-induced muscle wasting.

Project description:BackgroundAdipose tissue may have different metabolic and endocrine functions depending on the region of the body in which it is located. While visceral or intra-abdominal fat has been found to contribute to leptin concentrations, insulin resistance and obesity-related diseases, there are only a few imaging studies documenting the preferential distribution of body fat to either the intra-abdominal or subcutaneous compartments in dogs. This study aimed to determine if CT-measured abdominal fat distributed preferentially to the visceral space (V) relative to the subcutaneous space (SQ), with increasing DXA-determined total body fat percentage; and if ultrasound measurements of the ventral midline subcutaneous (SAT) and visceral adipose thickness (VAT) can be used to estimate the distribution of fat to the subcutaneous and visceral abdominal spaces, in a sample of 22 dogs with variable body condition.ResultsMultivariate analysis showed no statistically significant correlation between visceral to subcutaneous fat ratio (V/SQ) and increasing total body fat percentage (??=???0.07, p?=?0.733), but strong correlation with age (??=?0.71 p?=?0.002). A substantial amount of variation for the ultrasound visceral adipose thickness to subcutaneous fat thickness (VAT/SAT) could be explained by both CT V/SQ and sex (R2Adjusted?=?0.477, p?=?0.001), with female dogs having significant lower VAT/SAT ratios compared to the male dogs (p?=?0.047). The ultrasound fat measurements appeared moderately reliable, but a larger sample number is required to confirm this.ConclusionsThe findings suggest that dogs with a relatively healthy to slightly overweight body condition score, distribute fat relatively similarly between their peritoneal (visceral) and subcutaneous abdominal compartments with increasing total body fat percentage. However, there was increased fat distribution to the peritoneal space relative to the subcutaneous space with increasing age. Further, abdominal ultrasound may be useful in estimating the ratio of fat distribution to both the abdominal visceral and subcutaneous spaces.

Dataset Information

Myocyte androgen receptors increase metabolic rate and improve body composition by reducing fat mass.

Publications

Myocyte androgen receptors increase metabolic rate and improve body composition by reducing fat mass.

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