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Nathan Goodyear

PLOS ONE: Probiotic Microbes Sustain Youthful Serum Testosterone Levels and Testicular ... - 0 views

journals.plos.org/...article

hormone hormones low T low Testosterone hypogonadism Testosterone probiotic L reuters probiotics Lactobacillus lactobacillus reuteri male aging

shared by Nathan Goodyear on 29 Apr 15 - No Cached
  • Studies in both humans and rodents, however, suggest that low testosterone is due to age-related lesions in testes rather than irregular luteinizing hormone metabolism
  • Various dietary factors and diet-induced obesity have been shown to increase the risk for late onset male hypogonadism and low testosterone production in both humans and mice
  • Testosterone deficiency and metabolic diseases such as obesity appear to inter-digitate in complex cause-and-effect relationships
  • ...28 more annotations...
  • dietary supplementation of aged mice with the probiotic bacterium Lactobacillus reuteri makes them appear to be younger than their matched untreated sibling mice
  • These results indicate that gut microbiota induce modulation of local gastrointestinal immunity resulting in systemic effects on the immune system which activate metabolic pathways that restore tissue homeostasis and overall health
  • all these studies we consistently observed that young and aged mice consuming purified L. reuteri organisms had particularly large testes and a dominant male behavior.
  • The testes of probiotic-fed aged mice were rescued from both seminiferous tubule atrophy and interstitial Leydig cell area reduction typical of the normal aging process. Preservation of testicular architecture despite advanced age or high-fat diet coincided with remarkably high levels of circulating testosterone. The beneficial effects of probiotic consumption were recapitulated by the depletion of the pro-inflammatory cytokine Il-17.
  • feeding of L. reuteri consistently increased the gonadal weights, consumption of a non-pathogenic strain of Escherichia coli (E. coli) K12 organisms did not affect testicular weight
  • mice with dietary L. reuteri supplements were rescued from diet-induced obesity and had normal body weight and lean physique
  • Despite the comparable numbers of ST profiles, we determined that testes from L. reuteri-treated mice had increased ST cross-sectioned profiles
  • the probiotic organism induced prominent Leydig cell accumulations in the interstitial tissue between the ST's
  • The probiotic-associated increase of interstitial Leydig cell areas was sustained with advancing age at 7 (CD vs CD+LR, P = 0.0025; CD+E.coli vs CD+LR, P = 0.0251) and 12 months
  • mice eating L. reuteri had profoundly increased levels of circulating testosterone regardless of the type of diet they consumed
  • blocking pro-inflammatory Il-17 signaling entirely recapitulates the beneficial effects of probiotics
  • previous studies we found that dietary probiotics counteract obesity [19] and age-related integumentary pathology [18] at least in part by down-regulating systemic pro-inflammatory IL-17A-dependent signaling
  • Testes histomorphometry and serum androgen concentration data were both suggestive of a probiotic-associated up-regulation of spermatogenesis in mice
  • Lactobacillus reuteri we discovered that aging male animals had larger testes compared to their age-matched controls
  • xamined testes of probiotic microbe-fed mice and found that they had less testicular atrophy coinciding with higher levels of circulating testosterone compared to their age-matched controls
  • Similar testicular health benefits were produced using systemic depletion of the pro-inflammatory cytokine Il-17 alone, implicating a chronic inflammatory pathway in hypogonadism
  • One specific aspect of this paradigm is reciprocal activities of pro-inflammatory Th-17 and anti-inflammatory Treg cells
  • Feeding of L. reuteri organisms was previously shown to up-regulate IL-10 levels and reduce levels of IL-17 [19] serving to lower systemic inflammation
  • insufficient levels of IL-10 may increase the risk for autoimmunity, obesity, and other inflammatory disease syndromes
  • Westernized diets are also low in vitamin D, a nutrient that when present normally works together with IL-10 to protect against inflammatory disorders
  • Physiological feedback loops apparently exist between microbes, host hormones, and immunity
  • The hormone testosterone has been shown to act directly through androgen receptors on CD4+ cells to increase IL-10 expression
  • studies in both humans and rodents suggest that hypogonadism is due to age-related lesions in testes rather than irregular LH metabolism
  • We postulate that probiotic gut microbes function symbiotically with their mammalian hosts to impart immune homeostasis to maintain systemic and testicular health [34]–[35] despite suboptimal dietary conditions.
  • Dietary factors and diet-induced obesity were previously shown to increase risk for age-associated male hypogonadism, reduced spermatogenesis, and low testosterone production in both humans and mice [2]–[4], [8]–[11], [14]–[17], phenotypic features that in this study were inhibited by oral probiotic therapy absent milk sugars, extra protein, or vitamin D supplied in yogurt.
  • Similar beneficial effects of probiotic microbes on testosterone levels and sperm indices were reported in male mice that had been simultaneously supplemented with selenium
  • L. reuteri-associated prevention of age- and diet-related testicular atrophy correlates with increased numbers and size of Leydig cells
  • the initial changes of testicular atrophy begin to occur in mice from the age of 6 moths onwards [7] and indicates that the trophic effect of L. reuteri on Leydig cells is a key event which precedes and prevents age-related changes in the testes of mice. This effect is reminiscent of earlier studies describing Leydig cell hyperplasia and/or hypertrophy in the mouse and the rat testis that were achievable by the administration of gonadotropins, including human chorionic gonadotropin, FSH and LH
  • Nathan Goodyear on 29 Apr 15
     
    Fascinating study on how the addition of Lactobacillus reuteri increased Testicular size, prevented testicular atrophy, increased serum Testosterone production and protected against diet-induced/obesity-induced hypogonadism.  This was a mouse model
Nathan Goodyear

Review of health risks of low testosterone and testosterone administration - 0 views

www.ncbi.nlm.nih.gov/...PMC4391003

low Testosterone low T Testosterone men male hormone hormones health

shared by Nathan Goodyear on 28 Apr 15 - No Cached
  • Hypogonadism may be defined either as serum concentration of T (either total T, bioavailable T or free T) or as low T plus symptoms of hypogonadism
  • The Baltimore Longitudinal Study on Aging reported the incidence of total serum T < 325 ng/dL to be 20% for men in their 60s, 30% for men in their 70s and 50% for men over 80
  • The Massachusetts Aging Male Study reported that 12.3% of men aged 40 to 70 had a total serum T of < 200 ng/dL with 3 or more symptoms of hypogonadism
  • ...19 more annotations...
  • The Boston Area Community Health Study reported that 5.6% of men aged 30 to 70 were hypogonadal, as defined by total serum T < 300 ng/dL; or, free serum T < 5 ng/dL plus 3 or more symptoms of hypogonadism
  • In a health screening project among 819 men in Taiwan, the prevalence of hypogonadism (total serum T < 300 ng/dL) ranged from 16.5% for men in their 40s, 23.0% for men in their 50s, 28.9% for men in their 60s, and 37.2% for men older than 70 years of age
  • The prevalence of hypogonadism among men in Taiwan is higher than the prevalence reported in the Massachusetts Male Aging Study
  • CAG repeat sequence, within the androgen receptor (AR). Rajender et al[12] reviewed over 30 studies on the AR trinucleotide repeat and infertility
  • suggestion that CAG repeat length may determine androgen responsiveness, this issue is not clearly settled
  • reported prevalence of low T in older men range from 5.6% to 50%
  • Those in the hypogonadal group (n = 4269) had direct health care costs, that exceeded the eugonadal group (n = 4269) by an average of $7100 over the course of the observation window
  • higher economic burden and presence of co-morbidities for hypogonadism
  • minor to moderate improvements in lean mass and muscle strength
  • increased bone mineral density
  • modest enhancement in sexual function
  • reduced adiposity
  • lessening of depressive symptoms
  • Meta-analyses of clinical TRT trials as of 2010 have identified three major adverse events resulting from TRT: (1) polycythemia; (2) an increase in prostate-related events; and (3) and a slight reduction in serum high-density lipoprotein (HDL) cholesterol
  • polycythemia (> 3.5-fold increase in risk
  • TRT produced a 40% prostate enlargement in older hypogonadal male Veterans over 12 mo
  • no published analysis has reported measurable increases in prostate cancer risk or Gleason score in men undergoing TRT, or in hypogonadal men with a history of prostate cancer undergoing TRT
  • the prostate which highly expresses the type II 5α-reductase enzyme. Inhibition of this enzyme via finasteride (a type II 5α-reductase inhibitor) or dutasteride (a dual type I and II 5α-reductase inhibitor) reduces circulating DHT 50%-75% and > 90%, respectively[47], and reduces prostate mass[48] and prostate cancer risk
  • Normally estradiol partially regulates testosterone levels, at the hypothalamus, blunting LH and FSH release from the pituitary. As a selective estrogen receptor modulator, CC interrupts this pathway, and consequently there is a greater stimulation for the production of testosterone in Leydig cells
    • Nathan Goodyear
      Nathan Goodyear on 28 Apr 15
       
      this would only apply if E1 and/or E2 levels were elevated, which the authors make no mention of.
  • Nathan Goodyear on 28 Apr 15
     
    to be read
Nathan Goodyear

Longitudinal and cross-sectional rel... [J Clin Endocrinol Metab. 2014] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...24552220

low T Testosterone elderly men E1 Estrone health male hormone hormones men's health

shared by Nathan Goodyear on 24 Feb 14 - No Cached
  • Nathan Goodyear on 24 Feb 14
     
    This study found that lower TT and E1 associated with more "poor health" as defined by questionnaire.  The conclusion might lead one to think that Estrogen therapy is need in men.  Eightly percent of estrogen production in men occurs from Testosterone.  If Testosterone declines, then estrogen production will likewise decline.  A simple fact that the authors did not comment on.  Also, E1 binds with high affinity to ER alpha, which is pro-inflammatory and pro-proliferative: neither of which is a positive health benefit.   This appears to point more to a broad HPA suppression as an association to the "poor health".
Nathan Goodyear

Age Trends in the Level of Serum Testosterone and Other Hormones in Middle-Aged Men: Lo... - 0 views

jcem.endojournals.org/...589.abstract

level serum testosterone trends hormones male aging study hormone low T low Testosterone health massachusetts

shared by Nathan Goodyear on 10 Dec 12 - No Cached
  • Nathan Goodyear on 10 Dec 12
     
    This study found that in longitudinal studies, testosterone decline accelerated compared to cross sectional studies.  They concluded that decreasing health could be the explanation.  But, what if the decline in testosterone explained the decreasing health?
Nathan Goodyear

Serum levels of sex hormone-binding globulin (SHBG) are not associated with lower level... - 0 views

www.ncbi.nlm.nih.gov/...15807883

SHBG Testosterone men male hormone hormones

shared by Nathan Goodyear on 01 May 15 - No Cached
  • Nathan Goodyear on 01 May 15
     
    Age increases SHBG.  This study doesn't find a correlation with non-SHBG Testosterone in "health" men.  The term health is probably key.
Nathan Goodyear

http://archives.esf.org/fileadmin/Public_documents/Publications/SPB40_MaleReproductiveH... - 0 views

archives.esf.org/...B40_MaleReproductiveHealth.pdf

men male hormones fertility sperm male fertility male reproduction male reproductive health

shared by Nathan Goodyear on 09 Feb 17 - No Cached
  • Nathan Goodyear on 09 Feb 17
     
    good analysis of the declining sperm issue in men worldwide.
Nathan Goodyear

Testosterone deficiency syndrome and cardiovascular health: An assessment of beliefs, k... - 0 views

www.ncbi.nlm.nih.gov/...PMC3929476

low T Testosterone cardiovascular disease physicians men male hormone hormones

shared by Nathan Goodyear on 03 Mar 14 - No Cached
  • The vast majority (88%) did not screen cardiac patients for TDS.
  • Testosterone deficiency has a prevalence of 7% in the general population, rising to 20% in elderly males
  • Males with CAD have lower testosterone levels than those with normal coronary angiograms of the same age,5 suggesting that the prevalence of testosterone deficiency is much higher in the CAD population
  • ...14 more annotations...
  • Men with hypertension, another established risk factor for CAD, have lower testosterone compared to normotensive men
  • Recent meta-analyses showed that testosterone levels are generally lower among patients with metabolic syndrome, regardless of the various definitions of metabolic syndrome that are used
  • Testosterone (total and bioavailable) and sex-hormone binding globulin (SHBG) are inversely associated with the prevalence of metabolic syndrome in men between the ages of 40 and 80, and this association persists across racial and ethnic backgrounds
  • ower levels of testosterone and SHBG predict a higher incidence of metabolic syndrome.
  • Low testosterone levels have been related to increased insulin resistance and cardiovascular mortality,12 even in the absence of overt type 2 diabetes mellitus.
  • testosterone levels (total and bioavailable) in middle-aged men are inversely correlated with insulin resistance
  • The Massachusetts Male Aging Study (MMAS) demonstrated that low levels of testosterone and SHBG are independent risk factors for the development of type 2 diabetes,
  • Andropausal men (age 58 ± 7 years) have a higher maximal carotid artery intima-media thickness
  • There is an inverse linear correlation between body mass index (BMI) and wait-to-hip ratio with testosterone and insulin-like growth factor-1 levels.
  • Testosterone supplementation for 1 year in hypogonadal men has been shown to cause a significant improvement in body weight, BMI, waist size, lipid profile, and C-reactive protein levels
  • TRT for 3 months in hypogonadal men with type 2 diabetes significantly improved fasting insulin sensitivity, fasting blood glucose and glycated hemoglobin.
  • Testosterone replacement can improve angina symptoms and delay the onset of cardiac ischemia, likely through a coronary vasodilator mechanism
  • ADT is associated with an increased risk of cardiovascular events, including myocardial infarction and cardiovascular mortality.
  • ADT significantly increases fat mass, decreases lean body mass,29,30 increases fasting plasma insulin and decreases insulin sensitivity31 and increases serum cholesterol and triglyceride levels
  • Nathan Goodyear on 03 Mar 14
     
    Startling study on the knowledge of Testosterone and cardiovascular disease in general practitioners and cardiologists in Canada.  Eight-eight percent did not screen patients with cardiovascular disease for low Testosterone.  A whopping 67% of physicians did not know that low T was a risk factor for cardiovascular disease, yet 62% believed Testosterone would increase exercise tolerance. The lack of knowledge displayed by physicians today is staggering and is an indictment of the governing bodies.  This was a survey conducted in Canada so there are obvious limitations to the strength/conclusion of this study.
Nathan Goodyear

Reproductive and developmental effects of p... [Crit Rev Toxicol. 2014] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...24903855

phthalates xenoestrogens xenoestrogen male hormone hormones

shared by Nathan Goodyear on 16 Jun 14 - No Cached
  • Nathan Goodyear on 16 Jun 14
     
    phthalates are xenoestrogens that is toxic to male reproductive health.
Nathan Goodyear

http://press.endocrine.org/doi/pdf/10.1210/jc.2014-1872 - 0 views

press.endocrine.org/...jc.2014-1872

low T Testosterone treatment therapy diabetes obesity men male hormone hormones

shared by Nathan Goodyear on 29 Jul 14 - No Cached
  • Nathan Goodyear on 29 Jul 14
     
    New study finds Testosterone therapy provides less than statistical significant improvement in constitutional/sexual symptoms, in obese men with type II diabetes with symptoms classified as mild-moderate with modest reductions in Total Testosterone.  This study highlights that low Testosterone is a biomarker of poor health and multiple comorbidities and that simply adding in Testosterone therapy will not cure all male woes.  The authors did state that ED and low T are separate issues and I will differ with them on this--they are in fact link.  This association may vary between individuals, but to flatly state they are completely separate issues is devoid of the fact that testosterone has been shown to reduce inflammatory cytokines and improve PDE5 therapy.  
Nathan Goodyear

Hypothalamic-Pituitary-Testicular Axis Disruptions in Older Men Are Differentially Link... - 0 views

press.endocrine.org/...jc.2007-1972

low T low Testosterone low T Testosterone aging LH hormone hormones men male SHBG

shared by Nathan Goodyear on 03 Sep 14 - No Cached
  • 0.4–2% annual decline
  • the age trend in free T was more substantial (−1.3% per annum)
  • The core hormonal pattern with increasing age is suggestive of incipient primary testicular dysfunction with maintained total T and progressively blunted free T associated with higher LH.
  • ...16 more annotations...
  • Obesity was associated with progressively lower total and free T independent of the simultaneous decrease in SHBG.
  • our data highlight the fact that LH was unchanged or even lower in older men in the face of lower T in obesity, suggesting that there may be a failure at the hypothalamic-pituitary level.
  • a change in BMI from nonobese to obese may be equivalent to a 15 yr fall in T.
  • This pattern supports the hypothesis that different underlying mechanisms influence the functions of the HPT axis: age predominantly affects testicular function, whereas obesity impairs hypothalamic/pituitary function.
  • the effects of aging on testicular function can be moderated by increased LH compensation for many decades
  • obesity impairs hypothalamic/pituitary function independent of age, arguably an adaptive response for which there should be no compensatory mechanism.
  • the concurrent but opposite (and separate) effects of obesity and age on SHBG
  • SHBG was negatively associated with increasing strata of obesity
  • Obesity is associated with insulin resistance (28), and the increased circulating insulin inhibits hepatic SHBG synthesis
  • the SHBG increase with age may be related to relative IGF-I deficiency (27), although this has not been directly proven.
  • Obesity is associated with peripheral and central insulin resistance (30) and proinflammatory cytokine production (TNFα and IL-6) from adipocytes (31) and central nervous system endocannibinoid release (32), all of which are potential candidates for abrogating hypothalamic endocrine and downstream reproductive axis functions.
    • Nathan Goodyear
      Nathan Goodyear on 03 Sep 14
       
      The HPA axis effect may be the result of inflammation.
  • The relationship between obesity and T can be bidirectional: low T may be the cause rather than consequence of obesity
  • chronic alcohol abuse is known to suppress LH (40), our data showed no significant association among the three hormones or SHBG and alcohol intake.
  • increase in total T in smokers occurs through a primary increase in SHBG with a compensatory rise in LH
  • the effects of obesity (BMI or waist circumference) was by far the most important determinant of variance in total T, whereas age per se was important for SHBG, LH, and free T with comorbidity and smoking being comparatively minor contributors
  • It is noteworthy that these predisposing lifestyle and health factors are modifiable. This implies that the apparent age-related decline in T may constitute a barometer of health and thus be potentially preventable and/or reversible.
  • Nathan Goodyear on 03 Sep 14
     
    Age induced decline in Testosterone is more associated with a decline in leydig cell function and thus elevated LH will be associated.  In contrast, obesity is more of a HPA axis disruption and thus LH may be normal to low.  The pulse amplitude is decrease.  No change in pulse frequency is noted.   With obesity, a decline in TT and fT was independent of SHBG. Aging is associated with a greater decrease in fT versus TT.
Nathan Goodyear

Nature Clinical Practice Endocrinology & Metabolism | Testosterone and ill-health in ag... - 0 views

www.nature.com/...ncpendmet1050.html

low T Testosterone health men male hormone hormones metabolic syndrome metabolic syndrome MetS insulin resistance diabetes aging

shared by Nathan Goodyear on 03 Mar 14 - No Cached
  • Levels of total and bioavailable testosterone and SHBG were reported to be inversely correlated with the prevalence of the metabolic syndrome in men aged 40–80 years
  • as were total testosterone and SHBG in men aged 65–96 years
  • and in a cross-sectional analysis of a large cohort of non-diabetic men aged 70–89 years
  • ...18 more annotations...
  • In longitudinal studies, decreased levels of total testosterone and SHBG predicted an increased incidence of metabolic syndrome in nonobese men
  • Free testosterone level is not associated with the prevalence of metabolic syndrome in middle-aged and older men
  • Levels of free, bioavailable and total testosterone are lower in men with T2DM than in age-matched controls,34, 35 and decreased total testosterone level predicts incident T2DM in middle-aged men.
  • men with T2DM commonly have low total or free testosterone levels
  • Total, bioavailable and free testosterone levels are inversely correlated with fasting insulin level and insulin resistance in middle-aged men without T2DM
  • total testosterone is positively correlated with insulin sensitivity in men with normal or impaired glucose tolerance or T2DM
  • low SHBG level is more strongly associated with metabolic syndrome than low total testosterone in aging men
  • the recognized association between low SHBG level and insulin resistance
  • Low levels of SHBG are also associated with smaller, denser LDL-cholesterol molecules in nondiabetic men,58 and were found to predict increased cardiovascular disease mortality in one study of older men
  • Low levels of SHBG might reflect obesity, insulin resistance and overall poor health
  • Compared with those who have normal testosterone levels, men aged 40 years or more with total testosterone levels <9.8 nmol/l or elevated LH level have greater CIMT
  • In men aged 73–94 years, total testosterone was inversely correlated with CIMT
  • a prospective analysis of men aged 73–91 years, progression of CIMT was not related to total testosterone level, but it was inversely related to free testosterone level
  • A study of men aged 55 years or more found that those with total and bioavailable testosterone levels in the highest tertile had a lower risk of severe aortic atherosclerosis (detected by radiography as abdominal aortic calcification) than those with the lowest testosterone levels.
  • a large study of men aged 69–80 years, those with total or free testosterone in the lowest quartile had increased odds of lower-extremity peripheral arterial disease
  • the possibility of reverse causation has to be considered, as systemic illness can result in decreased testosterone levels
  • previous case–control studies and longitudinal studies have failed to identify low testosterone levels as strong predictors of clinically significant coronary disease
  • Reviews of trials on testosterone therapy in men with either low or low-to-normal testosterone levels have not shown consistent beneficial effects either on lipid profiles or on actual cardiovascular events.24, 54, 55 These trials, however, have not been designed or powered to detect treatment-related differences in cardiovascular outcome
  • Nathan Goodyear on 03 Mar 14
     
    Declining Testosterone or low Testosterone is clearly associated with poor health in men.   Very nice review of the association between low Testosterone and metabolic dysfunction.  Low T is associated with increased metabolic syndrome, Diabetes, weight gain, insulin resistance...
Nathan Goodyear

Testosterone: a metabolic hormone in health and disease - 0 views

joe.endocrinology-journals.org/...R25.full

male hormone hormones testosterone hypogonadal-obesity-adipocytokine hypothesis

shared by Nathan Goodyear on 08 May 13 - No Cached
  • E2 and the inflammatory adipocytokines tumour necrosis factor α (TNFα) and interleukin 6 (IL6) inhibit hypothalamic production of GNRH and subsequent release of LH and FSH from the pituitary
  • Leptin, an adipose-derived hormone with a well-known role in regulation of body weight and food intake, also induces LH release under normal conditions via stimulation of hypothalamic GNRH neurons
  • In human obesity, whereby adipocytes are producing elevated amounts of leptin, the hypothalamic–pituitary axis becomes leptin resistant
  • ...39 more annotations...
  • there is evidence from animal studies that leptin resistance, inflammation and oestrogens inhibit neuronal release of kisspeptin
  • Beyond hypothalamic action, leptin also directly inhibits the stimulatory action of gonadotrophins on the Leydig cells of the testis to decrease testosterone production; therefore, elevated leptin levels in obesity may further diminish androgen status
  • Prostate cancer patients with pre-existing T2DM show a further deterioration of insulin resistance and worsening of diabetic control following ADT
  • ADT for the treatment of prostatic carcinoma in some large epidemiological studies has been shown to be associated with an increased risk of developing MetS and T2DM
  • Non-diabetic men undergoing androgen ablation show increased occurrence of new-onset diabetes and demonstrate elevated insulin levels and worsening glycaemic control
  • increasing insulin resistance assessed by glucose tolerence test and hypoglycemic clamp was shown to be associated with a decrease in Leydig cell testosterone secretion in men
  • The response to testosterone replacement of insulin sensitivity is in part dependent on the androgen receptor (AR)
  • Low levels of testosterone have been associated with an atherogenic lipoprotein profile, characterised by high LDL and triglyceride levels
  • a positive correlation between serum testosterone and HDL has been reported in both healthy and diabetic men
  • up to 70% of the body's insulin sensitivity is accounted for by muscle
  • Testosterone deficiency is associated with a decrease in lean body mass
  • relative muscle mass is inversely associated with insulin resistance and pre-diabetes
  • GLUT4 and IRS1 were up-regulated in cultured adipocytes and skeletal muscle cells following testosterone treatment at low dose and short-time incubations
  • local conversion of testosterone to DHT and activation of AR may be important for glucose uptake
  • inverse correlation between testosterone levels and adverse mitochondrial function
  • orchidectomy of male Wistar rats and associated testosterone deficiency induced increased absorption of glucose from the intestine
  • (Kelley & Mandarino 2000). Frederiksen et al. (2012a) recently demonstrated that testosterone may influence components of metabolic flexibility as 6 months of transdermal testosterone treatment in aging men with low–normal bioavailable testosterone levels increased lipid oxidation and decreased glucose oxidation during the fasting state.
  • Decreased lipid oxidation coupled with diet-induced chronic FA elevation is linked to increased accumulation of myocellular lipid, in particular diacylglycerol and/or ceramide in myocytes
  • In the Chang human adult liver cell line, insulin receptor mRNA expression was significantly increased following exposure to testosterone
  • Testosterone deprivation via castration of male rats led to decreased expression of Glut4 in liver tissue, as well as adipose and muscle
  • oestrogen was found to increase the expression of insulin receptors in insulin-resistant HepG2 human liver cell line
  • FFA decrease hepatic insulin binding and extraction, increase hepatic gluconeogenesis and increase hepatic insulin resistance.
  • Only one, albeit large-scale, population-based cross-sectional study reports an association between low serum testosterone concentrations and hepatic steatosis in men (Völzke et al. 2010)
  • This suggests that testosterone may confer some of its beneficial effects on hepatic lipid metabolism via conversion to E2 and subsequent activation of ERα.
  • hypogonadal men exhibiting a reduced lean body mass and an increased fat mass, abdominal or central obesity
  • visceral adipose tissue was inversely correlated with bioavailable testosterone
  • there was no change in visceral fat mass in aged men with low testosterone levels following 6 months of transdermal TRT, yet subcutaneous fat mass was significantly reduced in both the thigh and the abdominal areas when analysed by MRI (Frederiksen et al. 2012b)
  • ADT of prostate cancer patients increased both visceral and subcutaneous abdominal fat in a 12-month prospective observational study (Hamilton et al. 2011)
  • Catecholamines are the major lipolysis regulating hormones in man and regulate adipocyte lipolysis through activation of adenylate cyclase to produce cAMP
  • deficiency of androgen action decreases lipolysis and is primarily responsible for the induction of obesity (Yanase et al. 2008)
  • may be some regional differences in the action of testosterone on subcutaneous and visceral adipose function
  • proinflammatory adipocytokines IL1, IL6 and TNFα are increased in obesity with a downstream effect that stimulates liver production of CRP
  • observational evidence suggests that IL1β, IL6, TNFα and CRP are inversely associated with serum testosterone levels in patients
  • TRT has been reported to significantly reduce these proinflammatory mediators
  • This suggests a role for AR in the metabolic actions of testosterone on fat accumulation and adipose tissue inflammatory response
  • testosterone treatment may have beneficial effects on preventing the pathogenesis of obesity by inhibiting adipogenesis, decreasing triglyceride uptake and storage, increasing lipolysis, influencing lipoprotein content and function and may directly reduce fat mass and increase muscle mass
  • Early interventional studies suggest that TRT in hypogonadal men with T2DM and/or MetS has beneficial effects on lipids, adiposity and parameters of insulin sensitivity and glucose control
  • Evidence that whole-body insulin sensitivity is reduced in testosterone deficiency and increases with testosterone replacement supports a key role of this hormone in glucose and lipid metabolism
  • Impaired insulin sensitivity in these three tissues is characterised by defects in insulin-stimulated glucose transport activity, in particular into skeletal muscle, impaired insulin-mediated inhibition of hepatic glucose production and stimulation of glycogen synthesis in liver, and a reduced ability of insulin to inhibit lipolysis in adipose tissue
  • Nathan Goodyear on 08 May 13
     
    Great review of the Hypogonadal-obesity-adipocytokine hypothesis.
Nathan Goodyear

Testosterone suppresses ventricular remodeling and improves left ventricular function i... - 0 views

www.ncbi.nlm.nih.gov/...PMC4353801

Testosterone therapy heart heart health myocardial infarction heart attack male hormone hormones CVD cardiovascular disease

shared by Nathan Goodyear on 24 Mar 15 - No Cached
  • Nathan Goodyear on 24 Mar 15
     
    Animal model finds that Testosterone improves ventricular remodeling and function following myocardial infarction in male rats.  This similar finding has been found in human studies as well.   Testosterone therapy was found to lower BNP in this rat study.
trungtamnamkhoa

menhealthvn - Slashdot User - 1 views

slashdot.org/~menhealthvn

shared by trungtamnamkhoa on 05 Jul 19 - No Cached
  • trungtamnamkhoa on 05 Jul 19
     
    Male health is an important issue that directly affects the well-being of families and labor productivity in the whole society. Today, with the negative changes of the environment and work pressures, many diverse and complex male pathologies have arisen. However, while gynecological examinations are performed periodically by women, male medical examination is often not respected by men because of the subjectivity as well as reservations about psychology.
Nathan Goodyear

Low Testosterone at Time of Transplant Is Independent... [J Urol. 2014] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...24704018

low T Testosterone men male hormone hormones

shared by Nathan Goodyear on 09 Apr 14 - No Cached
  • Nathan Goodyear on 09 Apr 14
     
    More and more, low Testosterone is clearly a marker of poor health in men.  This study finds that low T at the time of renal transplant is associated with increase graft rejection/loss and patient death.  It appears to me that Testosterone levels should be a part of assessment for any man in poor health and/or headed for surgery.
Nathan Goodyear

Testosterone therapy affects Mexican American men differently - UNT Health Science Cent... - 0 views

www.hsc.unt.edu/...newsrelease.cfm

testosterone therapy brain health oxidative stress men male hormone hormones

shared by Nathan Goodyear on 10 Apr 14 - No Cached
  • Nathan Goodyear on 10 Apr 14
     
    This is the public announcement of a article yet to be published.  The study, yet unread, points to increase damage to brain health in those caucasian men with oxidative stress.  This was not found in mexican-Americans.  Until I read this study, that is all I will say here.  
Nathan Goodyear

Associations between Circulating Reproductive Hormones and SHBG and Prevalent and Incid... - 1 views

press.endocrine.org/...jc.2014-2464

metabolic syndrome metabolic syndrome men male hormone hormones health Testosterone DHT SHBG cFT free Testosterone

shared by Nathan Goodyear on 06 Oct 14 - No Cached
  • Nathan Goodyear on 06 Oct 14
     
    The best marker associated with MetS in older men was low SHBG. Low T, DHT, and cFT were found to be more biomarkers of poor health rather than causal.
Nathan Goodyear

Low testosterone is associated with poor health status in men with ... - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...25704864

low T Testosterone low Testosterone HIV fT3 poor health men male hormones hormone

shared by Nathan Goodyear on 02 Mar 15 - No Cached
  • Nathan Goodyear on 02 Mar 15
     
    Lower Testosterone levels are found in men with more advanced HIV.  This relationship is bidirectional.  This decreased biomarker is likely more a biomarker of poor health than one of a direct relationship.  As in the fT3 is lower in hypogonadal men versus eugonadal men.  This points to the significant problems in the way Testosterone is thought of and used in therapy for men today.  For many men, low T is the effect and not the cause.
Nathan Goodyear

Bisphenol A Effects on Estrogen Receptor β Expression: Implications in Prosta... - 0 views

www.niehs.nih.gov/...index.cfm

BPA bisphenol A ER-beta prostate estrogen receptors ER estrogen receptors cancer

shared by Nathan Goodyear on 21 Nov 12 - No Cached
  • Nathan Goodyear on 21 Nov 12
     
    Bisphenol A downgregulates ER-beta in male prostate.  This would increase pro-inlfmmatory/growth through ER-alpha theoretically and has implications  in prostate health.
Nathan Goodyear

Male reproductive health and environmental xenoestrogens. - 0 views

www.ncbi.nlm.nih.gov/...PMC1469672

male health environmental xenoestrogens low T

shared by Nathan Goodyear on 11 Mar 13 - No Cached
  • Nathan Goodyear on 11 Mar 13
     
    Older analysis, but this shows the suspect and literature, supporting an environmental component to declining testosterone levels in me.
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