Effects of Sequential Bouts of Resistance Exercise on Androgen Receptor Expression

Abstract

Three sequential bouts of heavy resistance exercise increases serum TST and are effective at up-regulating AR mRNA and protein expression that appears to correspond to subsequent increases in myofibrillar protein.

Association of vigorous physical activity with age-related, site-specific loss of thigh muscle in women: the HIREGASAKI study

“…These results coincided with those of previous studies [7][8][9][10] and suggest that site-specific muscle loss of the thigh was observed in the present sample. Furthermore, the QF:HM ratio was positively associated with the duration of vigorous exercise during daytime physical activities.…”

“…Interestingly, in the anterior and posterior regions of the thigh, age-related muscle loss was observed in the quadriceps but not in the hamstrings and adductors. 8 The etiology of sitespecific sarcopenia is multifactorial and complex. Several factors have been implicated such as declining anabolic hormone concentrations, nutritional deficiencies, chronic inflammation, and insulin resistance.…”

“…5,7 Decreased physical activity levels that occur with aging also contribute to sarcopenia. It is well established that hormonal receptors for mRNA and transcriptional activity are increased 8 and that there is reduced insulin resistance 9 in exercising muscles following an acute bout of exercise for sedentary individuals. There are therefore many important interrelationships between physical activity levels and other etiologic factors associated with health and aging that may contribute in varying degrees to the age-related loss of skeletal muscle mass in older populations.…”

Physiological elevation of endogenous hormones results in superior strength training adaptation

“…Androgen receptor mRNA and protein have been observed to increase after 1-3 strength training sessions where levels of serum testosterone was acutely elevated (Bamman et al 2001;Willoughby and Taylor 2004;Hulmi et al 2008;Spiering et al 2009). Furthermore, administration of testosterone (without strength training) increases the content of androgen receptors in animal muscles (Carson et al 2002;Lee et al 2003) and humans (Ferrando et al 2002).…”

Acute and Chronic Testosterone Responses to Physical Exercise and Training

“…However, increases in resting testosterone levels were not observed in middle-aged (Cadore et al 2008a) or elderly people (Häkkinen et al, 2000(Häkkinen et al, , 2001aKraemer et al, 1999). Chronic adaptations to ST apparently occur at the level of cellular androgen receptors (ARs), given that ARs present on muscle cells seem to increase in number in response to this type of training (Inoue et al, 1994;Willoughby & Taylor, 2004), and this adaptation may result in improved hormone-receptor interaction (Bamman et al, 2001;Willoughby & Taylor, 2004). Conversely, reductions in testosterone levels associated with increases in cortisol levels have been observed in response to aerobic training in athletes subjected to high-volume training (Maïmoun et al, 2003).…”