Testosterone Deficiency and Replacement

Abstract

In the human male, testosterone is the major circulating androgen. More than 95% of circulating testosterone is secreted by the testis with a production rate of 6–7 mg/day. The clinical effects of androgens are numerous, and testosterone deficiency is associated with a number of clinical abnormalities. Overt hypogonadism results in reductions in bone mineral density, alterations in body composition and effects on mood, aggressive behaviour, cognitive function, sexual function and several factors important for cardiovascular risk. Androgen replacement in this context is clearly beneficial, and numerous studies have demonstrated improvements in bone and muscle mass, reductions in body fat, and positive effects on quality of life following treatment. The benefits of therapy in men with milder degrees of hypogonadism, and elderly men with ‘physiological’ testosterone deficiency, are less clear-cut, and the appropriate biochemical cut-off below which replacement should be offered has not been clearly defined. Several options are available for androgen replacement in adult men. Oral testosterone, intramuscular injections, subcutaneous implants and transdermal therapy have all been used. Each mode of delivery has advantages and drawbacks and the choice between them will often depend on patient reference. Recent advances include the development of longer-acting intramuscular preparations, which offer more stable androgen levels with fairly infrequent injections, and testosterone gel which appears to provide transdermal replacement without a high incidence of skin reactions. This article will examine the evidence concerning the impact of male hypogonadism and the response to androgen therapy. The question of who to treat will be addressed with particular reference to mild hypogonadism and hypogonadism in the elderly. Finally, an overview of the different modes of replacement therapy will be presented.

Prevalence of Pituitary Hormone Dysfunction, Metabolic Syndrome, and Impaired Quality of Life in Retired Professional Football Players: A Prospective Study

“…51,52,54,55,[74][75][76][77][78][79][80] The benefits of testosterone therapy for men are clear and considered standard practice. 50,57,81 In addition, the high prevalence of MetS in retired football players is important because lifestyle changes may reverse some of these findings and improve the cardiovascular and metabolic disease risks that are associated with MetS. Lifestyle changes to reduce weight with appropriate hormonal supplement in these former athletes may improve not only QoL, but also decrease disease risks.…”

“…[49][50][51][52][53][54][55][56][57][58][59][60] In addition to poor QoL, both GHD and hypogonadism can contribute to decreased lean body mass, increased fat mass (in particular, visceral fat), and poor exercise capacity that further contribute to poor QoL, obesity, and MetS, increasing cardiovascular disease (CVD) risk. 51,54,57,[61][62][63][64][65][66][67][68][69][70] Studies have shown that MetS is associated with, and predicts the development of, low serum testosterone levels in men. 62,64,65,71 Five of 6 subjects with hypogonadism had MetS and obesity.…”

46,XY disorders of sex development (DSD)

“…Recent advances include the development of longer-acting intramuscular testosterone preparations, which offer more stable androgen levels with fairly infrequent injections. 88 Intramuscular depot injections of testosterone esters are widely used. We start testosterone replacement between 10 and 11 year, simulating normal puberty according to the child's psychological evaluation and height.…”

Association Between Serum Testosterone Concentration and Carotid Atherosclerosis in Men With Type 2 Diabetes

“…A few prospective clinical trials, some cross-sectional studies, and experimental studies suggest that testosterone has a beneficial effect on the development of atherosclerosis or its clinical manifestations in men (34). Large prospective trials and intervention studies are needed to better assess the metabolic and cardiovascular benefits of testosterone.…”