Androgen replacement in men with hypogonadism and erectile dysfunction.
ABSTRACT The prevalence of hypogonadism and erectile dysfunction (ED) increases with age. Hypogonadism also is frequently associated with decreased libido and ED. Testosterone replacement therapy for hypogonadal ED is effective in restoring sexual desire and erectile function, especially in younger and healthy men. It appears to be less effective in older men with comorbid diseases that may cause ED. Therapy should be individualized, considered carefully, and closely monitored because of potential risks, especially in older men. The FDA has approved several testosterone delivery systems. These include a buccal testosterone tablet, intra-muscular injections, transdermal and subcutaneous forms. There also are several promising experimental androgens under investigation including non-steroidal selective androgen receptor modulators (SARMs).
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ABSTRACT: Penile erection is a complicated event involving the regulation of corpus cavernosal smooth muscle tone. Recently, the small monomeric G-protein RhoA and its downstream effector Rho-kinase have been proposed to be important players for mediating vasoconstriction in the penis. RhoA/Rho-kinase increases MLC (myosin light chain) phosphorylation through inhibition of MLCP (MLC phosphatase) thereby increasing Ca2+ sensitivity. This review will outline the RhoA/Rho-kinase signalling pathway, including the upstream regulators, guanine nucleotide exchange factors, GDP dissociation inhibitors and GTPase-activating proteins. We also summarize the current knowledge about the physiological roles of RhoA/Rho-kinase in both male and female erectile tissues and its aberrations contributing to erectile dysfunction in several disease states. Understanding the RhoA/Rho-kinase signalling pathway in the regulation of erection is important for the development of therapeutic interventions for erectile dysfunction.Clinical Science 03/2006; 110(2):153-65. DOI:10.1042/CS20050255 · 5.63 Impact Factor
- Antioxidant-Antidiabetic Agents and Human Health, Edited by Oluwafemi Oguntibeju, 02/2014: pages 279-295; InTech., ISBN: 978-953-51-1215-0
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ABSTRACT: Hypogonadism is associated with impaired libido and erectile dysfunction in young men, but the causes of sexual dysfunction in older men are less well understood. To determine the prevalence and predictors of sexual problems in older men. Sexual problems, as assessed by a self-reported questionnaire. This was a population-based, cohort study of 3,274 community-dwelling men aged 75-95 years (mean 82 years) from Perth, Western Australia. Questionnaires in 2001-2004 and 2008-2009 assessed social and medical risk factors. Sex hormones were measured in 2001-2004. Predictors of sexual problems, measured in 2008-2009, were assessed cross-sectionally in the entire sample, and longitudinally in a subset of 1,744 men with sex hormone data. Sexual problems were highly prevalent, with 49.4% (95% confidence interval 47.7% to 51.1%) reporting erectile problems, 47.7% (45.9% to 49.4%) lacking interest in sexual activity, 38.7% (37.0% to 40.3%) unable to climax, and 20.4% (19.1% to 21.8%) anxious about their ability to perform sexually. Painful and unpleasurable sex were less common (<5%). Overall, 72.0% (70.5% to 73.6%) reported at least one problem. In multivariate binary logistic regression analyses, cardiovascular disease, diabetes, depression, prostate disorders, and insomnia were the factors most commonly associated with sexual problems. Low testosterone levels were associated with lack of interest in sex, but not with other complaints. Sexual problems are common in elderly men. Chronic disease, depression, and insomnia appear to be the main modifiable risk factors. Androgen deficiency is unlikely to be a major cause of sexual problems in this age group.Journal of Sexual Medicine 12/2011; 9(2):442-53. DOI:10.1111/j.1743-6109.2011.02565.x · 3.15 Impact Factor