Plasma adrenal, gonadal, and conjugated steroids before and after long-term overfeeding in identical twins

Is an Energy Surplus Required to Maximize Skeletal Muscle Hypertrophy Associated With Resistance Training

Resistance training is commonly prescribed to enhance strength/power qualities and is achieved via improved neuromuscular recruitment, fiber type transition, and/ or skeletal muscle hypertrophy. The rate and amount of muscle hypertrophy associated with resistance training is influenced by a wide array of variables including the training program, plus training experience, gender, genetic predisposition, and nutritional status of the individual. Various dietary interventions have been proposed to influence muscle hypertrophy, including manipulation of protein intake, specific supplement prescription, and creation of an energy surplus. While recent research has provided significant insight into optimization of dietary protein intake and application of evidence based supplements, the specific energy surplus required to facilitate muscle hypertrophy is unknown. However, there is clear evidence of an anabolic stimulus possible from an energy surplus, even independent of resistance training. Common textbook recommendations are often based solely on the assumed energy stored within the tissue being assimilated. Unfortunately, such guidance likely fails to account for other energetically expensive processes associated with muscle hypertrophy, the acute metabolic adjustments that occur in response to an energy surplus, or individual nuances like training experience and energy status of the individual. Given the ambiguous nature of these calculations, it is not surprising to see broad ranging guidance on energy needs. These estimates have never been validated in a resistance training population to confirm the "sweet spot" for an energy surplus that facilitates optimal rates of muscle gain relative to fat mass. This review not only addresses the influence of an energy surplus on resistance training outcomes, but also explores other pertinent issues, including "how much should energy intake be increased," "where should this extra energy come from," and "when should this extra energy be consumed." Several gaps in the literature are identified, with the hope this will stimulate further research interest in this area. Having a broader appreciation of these issues will assist practitioners in the establishment of dietary strategies that facilitate resistance training adaptations while also addressing other important nutrition related issues such as optimization of fuelling and recovery goals. Practical issues like the management of satiety when attempting to increase energy intake are also addressed.

Endogenous testosterone and mortality risk

In men, obesity and metabolic complications are associated with lower serum testosterone (T) and dihydrotestosterone (DHT) and an increased risk of, and mortality from, multiple chronic diseases in addition to cardiovascular disease (CVD). The causal interrelationships between these factors remain a matter of debate. In men with untreated congenital and lifelong forms of hypogonadotropic hypogonadism, there appears to be no increased risk. Men with Klinefelter's syndrome have an increased risk of various types of cancers, as well as CVD, which persist despite T therapy. In the absence of pathology of the hypothalamic-pituitary-gonadal axis, the effect of modest reductions in serum T in aging men is unclear. The prevalence of low serum T concentrations is high in men with cancer, renal disease, and respiratory disease and is likely to be an indicator of severity of systemic disease, not hypogonadism. Some population-based studies have found low serum T to be associated with a higher risk of deaths attributed to cancer, renal disease, and respiratory disease, while others have not. Although a meta-analysis of longitudinal studies has shown an association between low serum T and all-cause mortality, marked heterogeneity between studies limited a firm conclusion. Therefore, while a decrease in T particularly occurring later in life may be associated with an increase in all-cause and specific types of mortality in men, the differential effects, if any, of T and other sex steroids as compared to health and lifestyle factors are unknown at the current time.

Hypercortisolemic Depressed Women: Lean but Viscerally Obese?

BACKGROUND

Activation of the hypothalamic-pituitary-adrenal (HPA) system in depressed patients has been related to visceral adiposity. In contrast, low HPA system activity is associated with increased body fat in the general population. Our study intended to clarify whether HPA system activity is related to body weight and composition in depressed inpatients.

METHODS

In a cohort of 51 female and 20 male depressed inpatients, we measured saliva cortisol (HPA system activity), body mass index (BMI), waist circumference as well as body composition as reflected by bioimpedance.

RESULTS

In female patients, cortisol in saliva was negatively associated with fat-to-muscle ratio and BMI.

CONCLUSION

In depressed inpatients, especially women, there is evidence that activation of the HPA system is related to relatively low body weight and low body fat content.

Predictors of body composition and body energy changes in response to chronic overfeeding

Objective

We have previously shown that 24 young lean men (12 pairs of identical twins) subjected to a standardized 353 MJ (84 000 kcal) overfeeding protocol over 100 days exhibited individual differences in body weight and composition gains. The mean (+SD) gains in fat mass (FM) and fat-free mass (FFM) were 5.4+1.9 kg and 2.7+1.5 kg for a total body energy (BE) gain of 221+75 MJ representing 63% of the energy surplus consumed. We report here on the most important baseline correlates of these overfeeding-induced changes with the aim of identifying biomarkers of the response.

Results

Baseline maximal oxygen uptake per kilogram body mass was negatively correlated with gains in weight, FM, and BE (all p<0.05). Enzyme activities indicative of skeletal muscle oxidative potential correlated with gains in FM and BE (all p<0.05). Baseline TSH levels in response to a TRH stimulation correlated positively with changes in FM-to-FFM ratio (p<0.05). Plasma concentrations of androstenediol-sulfate, dehydroepiandrosterone, and 17-hydroxy pregnenolone were negatively correlated with gains in FM and BE (0.01<p<0.05), while level of estrone was negatively and androsterone-glucoronide was positively correlated with FFM gains (p<0.05). Baseline leptin and abdominal fat cell size correlated positively with gains in weight, FM, and BE (p<0.05). When compared to the six highest BE gainers, the six lowest gainers exhibited higher thermic effect of a meal (TEM) and plasma levels of total testosterone, cortisol, estradiol, androstenedione, and androstenediol-sulfate (all p<0.05). High baseline levels of total TEM, testosterone, and androstenediol-sulfate were associated with lower FM gains whereas high baseline levels of FT4 and estrone were found in low-FFM gainers.

Conclusion

Although none of the variables exerted individually an overwhelmingly strong influence on overfeeding-induced changes, baseline FFM, maximal oxygen uptake, muscle oxidative capacity, androgens, and leptin levels were the most consistent significant biomarkers of the responsiveness to chronic overfeeding.

Do evolutionary life-history trade-offs influence prostate cancer risk? a review of population variation in testosterone levels and prostate cancer disparities

An accumulation of evidence suggests that increased exposure to androgens is associated with prostate cancer risk. The unrestricted energy budget that is typical of Western diets represents a novel departure from the conditions in which men's steroid physiology evolved and is capable of supporting distinctly elevated testosterone levels. Although nutritional constraints likely underlie divergent patterns of testosterone secretion between Westernized and non-Western men, considerable variability exists in men's testosterone levels and prostate cancer rates within Westernized populations. Here, I use evolutionary life history theory as a framework to examine prostate cancer risk. Life history theory posits trade-offs between investment in early reproduction and long-term survival. One corollary of life history theory is the 'challenge hypothesis', which predicts that males augment testosterone levels in response to intrasexual competition occurring within reproductive contexts. Understanding men's evolved steroid physiology may contribute toward understanding susceptibility to prostate cancer. Among well-nourished populations of Westerners, men's testosterone levels already represent an outlier of cross-cultural variation. I hypothesize that Westernized men in aggressive social environments, characterized by intense male-male competition, will further augment testosterone production aggravating prostate cancer risk.

Impaired hypothalamic-pituitary-gonadal axis function in men with diabetes mellitus

In view of association of diabetes mellitus and male infertility, present study was designed to investigate the functional status of hypothalamic pituitary gonadal (HPG) axis in diabetic men. Thirty-five diabetic men (BMI 22.24±0.21) in the age group 20-40 (30.6±4.7) years were selected. Twenty-five healthy men (BMI 23.85±0.25), in the same age group (29.5±4.8) served as control. Blood samples were collected for hormonal and biochemical estimations. Diabetic men had significantly low serum testosterone with low LH and FSH, hypercholesterolemia, hypertriglyceridemia, hypoalbuminemia and increased oxidative stress. Low serum testosterone in diabetic men was accompanied by low LH and FSH; the inability of the pituitary gland to respond appropriately to a decline in testosterone implying central effect of high serum glucose on the interaction between the nervous and endocrine system. Nutritional deficiency, increased oxidative stress and increased aromatase activity due to excessive body fat might have also contributed to low serum testosterone.

Connecting the Lines between Hypogonadism and Atherosclerosis

Epidemiological studies show that atherosclerotic cardiovascular disease is a leading cause of morbidity and mortality worldwide and point to gender differences with ageing males being at highest risk. Atherosclerosis is a complex process that has several risk factors and mediators. Hypogonadism is a commonly undiagnosed disease that has been associated with many of the events, and risk factors leading to atherosclerosis. The mechanistic relations between testosterone levels, atherosclerotic events, and risk factors are poorly understood in many instances, but the links are clear. In this paper, we summarize the research journey that explains the link between hypogonadism, each of the atherosclerotic events, and risk factors. We look into the different areas from which lessons could be learned, including epidemiological studies, animal and laboratory experiments, studies on androgen deprivation therapy patients, and studies on testosterone-treated patients. We finish by providing recommendations for the clinician and needs for future research.

Bioactive androgens and glucuronidated androgen metabolites are associated with subcutaneous and ectopic skeletal muscle adiposity among older black men

Aging is associated with declining serum levels of androgenic hormones and with increased skeletal muscle fat infiltration, an emerging risk factor for type 2 diabetes mellitus (T2DM). Androgens regulate fat mass and glucose homeostasis, but the effect of androgenic hormones on skeletal muscle fat infiltration is largely unknown. Thus, the aim of the current study was to examine the association of serum androgens and their precursors and metabolites with skeletal muscle fat infiltration and T2DM in a black male population group at high risk of T2DM. Serum androgens, estrogens, and androgen precursors and metabolites were measured using mass spectrometry; and calf skeletal muscle fat distribution (subcutaneous and intermuscular fat; skeletal muscle density) was measured using quantitative computed tomography in 472 Afro-Caribbean men 65 years and older. Bioactive androgens, testosterone, free testosterone, and dihydrotestosterone were associated with less skeletal muscle fat infiltration (r = -0.14 to -0.18, P < .05) and increased skeletal muscle density (r = 0.10 to 0.14, P < .05), independent of total adiposity. In addition, glucuronidated androgen metabolites were associated with less subcutaneous fat (r = -0.11 to -0.15, P < .05). Multivariate logistic regression analysis identified an increased level of 3α-diol-3 glucuronide (odds ratio = 1.38, P < .01) and a decreased level of dihydrotestosterone (odds ratio = 0.66, P < .01) to be significantly associated with T2DM. Our findings suggest that, in elderly black men, independent of total adiposity, bioactive androgens and glucuronidated androgen metabolites may play previously unrecognized role in skeletal muscle fat distribution. Longitudinal studies are needed to further evaluate the relationship between androgens and androgen metabolites with changes in skeletal muscle fat distribution with aging and the incidence of T2DM.

Long-term effects of calorie restriction on serum sex-hormone concentrations in men

Calorie restriction (CR) slows aging and consistently reduces circulating sex hormones in laboratory animals. However, nothing is known regarding the long-term effects of CR with adequate nutrition on serum sex-hormone concentration in lean healthy humans. In this study, we measured body composition, and serum total testosterone, total 17-beta-estradiol, sex hormone-binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEA-S) concentrations in 24 men (mean age 51.5 +/- 13 years), who had been practicing CR with adequate nutrition for an average of 7.4 +/- 4.5 years, in 24 age- and body fat-matched endurance runners (EX), and 24 age-matched sedentary controls eating Western diets (WD). We found that both the CR and EX volunteers had significantly lower body fat than the WD volunteers (total body fat, 8.7 +/- 4.2%; 10.5 +/- 4.4%; 23.2 +/- 6.1%, respectively; P = 0.0001). Serum total testosterone and the free androgen index were significantly lower, and SHBG was higher in the CR group than in the EX and WD groups (P < or = 0.001). Serum 17beta-estradiol and the estradiol:SHBG ratio were both significantly lower in the CR and EX groups than in the WD group (P < or = 0.005). Serum DHEA-S concentrations were not different between the three groups. These findings demonstrate that, as in long-lived CR rodents, long-term severe CR reduces serum total and free testosterone and increases SHBG concentrations in humans, independently of adiposity. More studies are needed to understand the role of this CR-mediated reduction in sex hormones in modulating the pathogenesis of age-associated chronic diseases such as cancer and the aging process itself.