borninawonder
Dutch Bodybuilder
- Lid sinds
- 6 apr 2004
- Berichten
- 720
- Waardering
- 14
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Receptor downgrading betreffende anabolen is dus achterhaald.
Als je de studies op Pubmed erop naslaat kan iedereen lezen dat er receptoren bijkomen door anabolengebruik.
Goeie post Krieltje !
ja right...........gewoon gelul net als dat cortisol verhaal gewoon zo overdreven,alsof je een raket in elkaar knutseld,gewoon te ver gezocht. Pro doet gewoon 52 weken round.
Jij bent dus de student laat jij dan iets zien. En ja het vindt plaats maar in welke mate dat is de vraag?
Waarom doe je een aanname dat ik nog nooit zo`n boek heb gelezen? Zo blijven we ping pongen ik vraag jou om iets te plaatsen omdat jij aangeeft de specialist te zijn.
Anyway ik ontken het niet alleen de vraag is in welke mate.
Als je down/upregulatie kreeg dan werkten onze eigen hormonen en neurotransmitters al lang niet meer.
Ik nam helemaal niet aan dat je nooit een fysiologieboek open had geslagen.. Jij vroeg om een voorbeeld en dat was m'n sugestie..
Ik pretendeer niet een specialist te zijn..
Ik ben druk vanaf m'n iPhone aan t typen.. Zodra ik thuis ben zal ik wel wat stof posten
Homologous up-regulation of androgen receptor expression by androgen in vascular smooth muscle cells.
Ma R, Wu S, Lin Q.
Department of Cardiology, Nanfang Hospital, Guangzhou, China.
Abstract
OBJECTIVE: Androgens play an important role in the arterial vascular system, and androgen receptors (AR) have been identified in vascular smooth muscle cells (VSMCs). This study examined the effects of testosterone exposure on AR gene expression in cultured rat aortic smooth muscle cells. METHODS: Changes in AR protein and messenger RNA (mRNA) levels after androgen exposure were determined using immunoblotting and Northern blotting analysis respectively. RESULTS: Treatment of synchronized VSMCs with testosterone increased both cytoplasmic and nuclear AR protein expression in a dose- and time-dependent fashion, whereas exposure of VSMCs to androgen for 10 min induced a transient down-regulation of AR protein. Meanwhile, AR mRNA level was also up-regulated, but to a much smaller extent. Pretreatment with transcription inhibitor and translation inhibitor repressed cytoplasmic AR protein levels to 46 and 12% (means) of the androgen treatment control level respectively. Furthermore, androgen up-regulation of intracellular AR protein was partially inhibited by androgen antagonist. CONCLUSIONS: Androgen increases AR expression in VSMCs at the level of both transcription and non-transcription. Copyright 2005 S. Karger AG, Basel.
Androgen receptor in human skeletal muscle and cultured muscle satellite cells: up-regulation by androgen treatment.
Sinha-Hikim I, Taylor WE, Gonzalez-Cadavid NF, Zheng W, Bhasin S.
Division of Endocrinology, Metabolism, and Molecular Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California 90059, USA.
Abstract
Androgens stimulate myogenesis, but we do not know what cell types within human skeletal muscle express the androgen receptor (AR) protein and are the target of androgen action. Because testosterone promotes the commitment of pluripotent, mesenchymal cells into myogenic lineage, we hypothesized that AR would be expressed in mesenchymal precursor cells in the skeletal muscle. AR expression was evaluated by immunohistochemical staining, confocal immunofluorescence, and immunoelectron microscopy in sections of vastus lateralis from healthy men before and after treatment with a supraphysiological dose of testosterone enanthate. Satellite cell cultures from human skeletal muscle were also tested for AR expression. AR protein was expressed predominantly in satellite cells, identified by their location outside sarcolemma and inside basal lamina, and by CD34 and C-met staining. Many myonuclei in muscle fibers also demonstrated AR immunostaining. Additionally, CD34+ stem cells in the interstitium, fibroblasts, and mast cells expressed AR immunoreactivity. AR expression was also observed in vascular endothelial and smooth muscle cells. Immunoelectron microscopy revealed aggregation of immunogold particles in nucleoli of satellite cells and myonuclei; testosterone treatment increased nucleolar AR density. In enriched cultures of human satellite cells, more than 95% of cells stained for CD34 and C-met, confirming their identity as satellite cells, and expressed AR protein. AR mRNA and protein expression in satellite cell cultures was confirmed by RT-PCR, reverse transcription and real-time PCR, sequencing of RT-PCR product, and Western blot analysis. Incubation of satellite cell cultures with supraphysiological testosterone and dihydrotestosterone concentrations (100 nm testosterone and 30 nm dihydrotestosterone) modestly increased AR protein levels. We conclude that AR is expressed in several cell types in human skeletal muscle, including satellite cells, fibroblasts, CD34+ precursor cells, vascular endothelial, smooth muscle cells, and mast cells. Satellite cells are the predominant site of AR expression. These observations support the hypothesis that androgens increase muscle mass in part by acting on several cell types to regulate the differentiation of mesenchymal precursor cells in the skeletal muscle.
Hehehe, ben wel benieuwd waar Brinta mee aankomt. Tis natuurlijk altijd even te verifieren of het klopt of niet.
Mack was trouwens ook aan het zoeken, duurt wel lang trouwens.


