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Nathan Goodyear

Testosterone relaxes coronary arteries by opening the large-conductance, calcium-activa... - 0 views

ajpheart.physiology.org/...H1720.full

testosterone vasodilation DHT androgens calcium channels potassium channels

shared by Nathan Goodyear on 14 May 13 - No Cached
  • Nathan Goodyear on 14 May 13
     
    The androgens testosterone and DHT elicit vasodilation via calcium and potassium channel activation.  The vasodilatory effect of the androgens is through, in part, due to K activated Ca channels.  Also of note, DHT had the same effect and DHT cannot be aromatized to estrogen.
Nathan Goodyear

Induction of Testicular Aromatization by Luteinizing Hormone in Mature Rats - 0 views

endo.endojournals.org/...431

hormone hormones LH testicle luteinizing hormone aromatase aromatization testicular

shared by Nathan Goodyear on 11 Jun 13 - No Cached
  • Nathan Goodyear on 11 Jun 13
     
    very interesting study in rats.  LH induced a dose-dependent increase in testicular estrogen production through aromatase activity.  Yes, LH stimulates the leydig cells to produce testosterone, but there is a point at which LH will actually increase aromatase activity and thus estrogen production at the testicular level.
Nathan Goodyear

acute stimulation of aromatization in Leydig cells by human chorionic gonadotropin in v... - 0 views

www.pnas.org/...4460.full.pdf

HCG aromatase aromatization leydig cells human chorionic gonadotropin hormone hormones men male

shared by Nathan Goodyear on 11 Jun 13 - No Cached
  • Nathan Goodyear on 11 Jun 13
     
    Granted, this is a in vitro study, but this study found that HCG stimulated increased leydig cell estrogen production through stimulation of aromatase activity.
Nathan Goodyear

Chemistry and Structural Biology of Androgen Receptor - 0 views

www.ncbi.nlm.nih.gov/...PMC2096617

androgens Testosterone DHT dihydrotestosterone AR androgen receptors male hormones hormones

shared by Nathan Goodyear on 28 Sep 16 - No Cached
  • Healthy adult men typically produce approximately 3–10 mg of testosterone per day
  • circulating levels ranging from 300 to 700 ng/dL in eugonadal men
  • endogenous testosterone secretion is pulsatile and diurnal
  • ...15 more annotations...
  • highest concentration occurring at about 8:00 a.m. and the lowest at about 8:00 p.m.
  • Average serum concentrations and diurnal variation in testosterone diminish as men age
  • 40% is sequestered with high affinity to sex hormone-binding globulin (SHBG)
  • almost 60% is bound with low affinity to albumin
  • 2% as free, unbound hormone
  • 5α-DHT has even greater binding affinity to sex hormone-binding globulin than does testosterone
  • 5α-DHT is only about 5% as abundant in the blood as testosterone and is largely derived from peripheral metabolism of testosterone
  • Both 5α-reduction and aromatization are irreversible processes
  • Approximately 90% of an oral dose of testosterone is metabolized before it reaches the systemic circulation
  • there are three modes of action of testosterone. It may directly act through AR in target tissues where 5α-reductase is not expressed, be converted to 5α-DHT (5–10%) by 5α-reductase before binding to AR, or be aromatized to estrogen (0.2%) and act through the estrogen receptor
  • 5α-DHT is a more potent AR ligand than testosterone
  • has 2–10-fold higher potency than testosterone in androgen-responsive tissues
  • estrogen plays a major role in regulating metabolic process,74,75 mood and cognition,76 cardiovascular disease,77,78 sexual function including libido,79 and bone turnover in men
  • Free testosterone is considered the most “biologically active” form
  • testosterone is the major androgen that acts in the “DHT-independent” tissues, such as skeletal muscle, where 5α-reductase is not expressed or is expressed at a very low level
  • Nathan Goodyear on 28 Sep 16
     
    good review of androgens and AR.
Nathan Goodyear

11-Ketotestosterone Is a Major Androgen Produced in Human Gonads: The Journal of Clinic... - 0 views

press.endocrine.org/...jc.2016-2311

testosterone 11-ketotestosterone hormones

shared by Nathan Goodyear on 17 Oct 16 - No Cached
  • Nathan Goodyear on 17 Oct 16
     
    Only abstract available here; 11-ketotestosterone found not to be susceptible to aromatase activity as is testosterone.  This was a breast cell culture study.  It was found to actually inhibit cell proliferation in opposition to aromatized testosterone.
Nathan Goodyear

Urological Research, Volume 15, Number 3 - SpringerLink - 0 views

www.springerlink.com/...r414480g0m356293

aromatase aromatase inhibitor estrogen men prostatitis BPH prostate cancer

shared by Nathan Goodyear on 02 May 12 - No Cached
  • Nathan Goodyear on 02 May 12
     
    aromatization of androstenedione to estrogen shown to play role in prostatitis, BPH, and prostate cancer.  In this study, they looked at aromatase inhibition to slow this process.
Nathan Goodyear

Adverse Events Associated with Testosterone Administration - NEJM - 0 views

www.nejm.org/...NEJMoa1000485

testosterone therapy treatment replacement low T cardiovascular events

shared by Nathan Goodyear on 01 Feb 12 - No Cached
  • Nathan Goodyear on 01 Feb 12
     
    Testosterone therapy shown to increase cardiovascular events in elderly men. No comment in study if they evaluated the aromatization of the replacement therapy to estrogen.  I anticipate that this would explain the increase events.
Nathan Goodyear

ScienceDirect - Toxicology Letters : Ex vivo study of incorporation into adipocytes and... - 0 views

www.sciencedirect.com/science

PBA obesity overweight polycyclic aromatic hydrocarbons

shared by Nathan Goodyear on 06 Apr 11 - No Cached
  • we therefore suggest that B[a]P may play a central role in carcinogenesis not only by inducing cancer through its mutagenic properties, but also by increasing the bioaccumulation capacity of the adipose tissue mass.
  • Nathan Goodyear on 06 Apr 11
     
    PBA plays role in increased fat mass
Nathan Goodyear

Beyond the male sex hormone: deciphering the metabolic and vascular actions of testoste... - 0 views

joe.endocrinology-journals.org/...C1.full

AR androgen receptors androgen receptor testosterone androgen receptors Diabetes metabolic syndrome MetS CVD cardiovascular disease men hormone hormones male

shared by Nathan Goodyear on 08 May 13 - No Cached
  • androgen deprivation therapy results in unfavorable changes in body composition, insulin resistance, and dyslipidemia and predisposes men to develop atherosclerosis and an increased risk of cardiovascular mortality
  • The hypogonadal–obesity cycle hypothesis was originally proposed by Cohen in 1999 to explain the relationship between low testosterone levels and metabolic disease. It was based on the finding that obesity impairs testosterone levels by increasing the aromatization of testosterone to estradiol, while low testosterone levels promote increased fat deposition
  • adipocytokines contribute to low testosterone levels as well as to the processes underlying metabolic syndromes and type 2 diabetes
  • ...15 more annotations...
  • hypogonadal–obesity–adipocytokine hypothesis
  • The presence of estradiol and the adipocytokines TNF-α, IL6, and leptin (as a result of leptin resistance in obesity) inhibits the hypothalamic–pituitary–testicular axis response to decreasing androgen levels
  • An increasing number of studies have illustrated the potential for applying metabolomics to the field of androgen research
  • As early as the 1940s, the therapeutic use of testosterone was reported to improve angina pectoris in men with coronary artery disease
  • most of the epidemiological studies reported increased cardiovascular risk and mortality in men with low testosterone levels
  • long-term testosterone replacement appears to be a safe and effective means of treating hypogonadal elderly men
  • a recent interventional trial showed that testosterone treatment was associated with decreased mortality when compared with no testosterone treatment in an observational cohort of men with low testosterone levels
  • a number of short-term studies conducted support the notion that testosterone therapy reduces the cardiovascular risk
  • The majority of animal studies support the hypothesis that the actions of testosterone on vascular relaxation are both endothelium-dependent and -independent vasodilatory effects
  • Endothelial-dependent actions of testosterone increase the expression or activity of endothelial nitric oxide synthase and enhance nitric oxide production, which in turn activates cyclic guanosine monophosphate to induce vasorelaxation in smooth muscle cells
  • Endothelial-independent mechanisms of testosterone are believed to occur primarily via inhibition of voltage-operated Ca2+ channels and/or activation of K+ channels in smooth muscle cells
  • Testosterone may also inhibit intracellular Ca2+ influx via store-operated Ca2+ channels by blocking the response to prostaglandin F2α
  • testosterone has demonstrated anti-inflammatory effects to protect against atherogenesis in animal studies
  • both genomic AR activation to modulate gene transcription and non-genomic activation to modulate the rapid intracellular signaling pathways of ion channels may mediate testosterone effects on vascular function and inflammation.
  • Butenandt & Ruzicka first showed how testosterone is synthesized and responsible for masculine characteristics in the early 1930s
  • Nathan Goodyear on 08 May 13
     
    Awesome review on the current understanding of Testosterone and Diabetes, metabolic syndrome, and CVD.  This article even goes into the literature on androgen receptors.
Nathan Goodyear

Estradiol in elderly men. [Aging Male. 2002] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...12198740

estrogen estradiol estrone men aromatase activity hormone

shared by Nathan Goodyear on 30 Apr 12 - No Cached
  • Plasma levels of estradiol do not necessarily reflect tissue-level activity
  • age-associated increased aromatization of testosterone
  • Estradiol levels are highly significantly positively related to body fat mass and more specifically to subcutaneous abdominal fat
  • Nathan Goodyear on 30 Apr 12
     
    Review of the sources of estrogens in men and the impact it has on a man's physiology.
Nathan Goodyear

Abnormal levels of serum dehydroepiandrosterone, estrone, and estradiol in men with rhe... - 0 views

www.jrheum.org/...2338.short

estradiol inflammation estrone aromatase activity aromatization rheumatoid arthritis RA men

shared by Nathan Goodyear on 07 Mar 12 - No Cached
  • Nathan Goodyear on 07 Mar 12
     
    elevated estradiol associated with increased inflammation symptoms in men with RA. Not found with estrone.
Nathan Goodyear

Transdermal testosterone replacement therapy in men - 0 views

www.ncbi.nlm.nih.gov/...PMC3891651

Testosterone replacement transdermal low T male hormone hormones

shared by Nathan Goodyear on 05 Feb 14 - No Cached
  • a recent study has suggested that it may sometimes be inaccurate because of abnormal fluctuation of other circulating androgens
    • Nathan Goodyear
      Nathan Goodyear on 05 Feb 14
       
      The authors are referencing the increase in the suggestions to use other testing techniques i.e. saliva.
  • Testosterone therapy can inhibit hepcidin transcription and is associated with increased iron incorporation into red blood cells and increased erythropoietin concentrations
  • Transdermal TRT has a more favorable adverse effect profile when compared to buccal testosterone formulations
  • ...13 more annotations...
  • testosterone concentrations should be checked 2–3 months after initiation of therapy and after adjusting the dose
  • the recommendation for injectable testosterone esters is to check the serum concentration midway between injections
  • it is recommended for serum testosterone to be evaluated 3 to 12 hours after application of the transdermal patch
  • Approximately 0.3% of testosterone is converted into estradiol by aromatase (CYP19A1)
  • a study from 1989 utilizing testosterone transdermally containing 5, 10, or 15 mg of testosterone showed that peak concentrations of testosterone were achieved 3 to 8 hours after scrotal application in hypogonadal men
  • measure serum testosterone any time after the patient has been on treatment with gel for at least 1 week
  • evaluate serum testosterone at the end of the dosing interval for testosterone pellets
  • increased amount of fat leads to increased extragonadal aromatase activity, resulting in increased concentrations of estradiol. High circulating concentrations of estradiol down regulate the HPG axis and decrease the amount of circulating testosterone
  • Up to 80% of plasma estradiol originates from aromatization of testosterone and less than 20% of estradiol in the circulation is secreted by the testes
  • A PSA concentration, digital rectal examination, and hematocrit should be performed at baseline and at 3 months, 6 months, then yearly after TRT is initiated.
  • It is used for many medications and has the advantage of high bioavailability, absence of hepatic first pass metabolism, increased therapeutic efficacy, and steadiness of plasma concentrations of the drug
  • If the hematocrit rises above 54%, treatment should be discontinued
  • elderly men having higher estradiol serum concentrations than postmenopausal women
Nathan Goodyear

Hormonal Modulation in Aging Patients with Erectile Dysfunction and Metabolic Syndrome - 0 views

www.ncbi.nlm.nih.gov/...PMC3888699

low T Testosterone hypogonadism MetS metabolic syndrome men male hormone hormones

shared by Nathan Goodyear on 05 Feb 14 - No Cached
  • Hypogonadism and MetS are strongly associated [12, 13, 16], having even been demonstrated that with the increasing number of MetS parameters there is a proportional raise in the incidence of hypogonadism
  • increasing number of MetS components is inversely associated with T levels
  • the presence of MetS did not prove to be a significant determinant of hypogonadism, as it did not lead to a decline in T levels, in MetS patients with already established hypogonadism, the increasing number of MetS features was associated with further decline in T
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  • In the setting of MetS, hypertriglyceridemia and increased WC have been reported as the most important determinants of hypogonadism
  • recent literature consistently associates obesity not only with higher risk of hypogonadism [4, 6, 27] but also with lower T levels
  • Visceral adiposity has been particularly related with reduction of T and SHBG levels (independent of other metabolic disorders)
  • WC was one of the MetS parameters with the greatest influence in T levels decrease, presenting itself as a strong risk factor for hypogonadism development
  • MetS-related T decline was not accompanied by an increase in pituitary LH levels, suggesting impairment in gonadotropin secretion
  • The molecules behind this smoothing compensatory effect of GnRH/LH are still unknown, but estrogens and insulin, as well as leptin, TNF-α, and other adipokines, were proposed candidates
  • fat stores undertake an increase aromatization of androgens, therefore raising estrogen levels [9, 15], which in turn decrease LH secretion
  • our data contradicts the concept that estradiol exerts a negative feedback on hypothalamic GnRH secretion
  • taking into account that high estradiol levels have already been described as the only abnormality in a subset of patients with ED, the hypothesis that the later might not only be caused by androgen deficiency is becoming increasingly evident
  • it has been reported that the chronic exposure to phosphodiesterase type 5 inhibitors (PDE5i), widely used for the treatment of ED, may influence serum estradiol levels
  • thyroid disorders (specially hyperthyroidism) have been related to ED and hypogonadism, and so must be considered in a sexual-dysfunction setting
  • It is clear from the current literature that collecting a more thorough hormonal panel might be a wise approach to further uncover hormonal relations
    • Nathan Goodyear
      Nathan Goodyear on 05 Feb 14
       
      outstanding point.  This hits to the point that Low T is the effect not the cause.
  • We concluded that in ED patients with hypogonadism and MetS, the attenuated response of HPG axis (normal or low LH levels) might not always be due to an underlying adiposity-dependent estrogen-raising effect.
  • our findings indicate that ED, aging, and estradiol might have a stronger connection than what is currently described in the literature.
  • this study underlines the importance of the collection of a full hormonal panel in ED men
  • Nathan Goodyear on 05 Feb 14
     
    low T strongly associated with metabolic syndrome in men.
Nathan Goodyear

Estrogen and prostate cancer: An eclipsed truth in an androgen-dominated scenario - Car... - 0 views

onlinelibrary.wiley.com/...abstract

aromatase aromatase activity Estradiol Estrogen ER alpha prostate cancer prostate cancer disease

shared by Nathan Goodyear on 21 Aug 13 - No Cached
  • Aberrant aromatase expression and activity has been reported in prostate tumor tissues and cells, implying that androgen aromatization to estrogens may play a role in prostate carcinogenesis or tumor progression
  • imbalance of their expression may be critical to determine the ultimate estrogen effects on prostate cancer cells
  • In prostate cancer, ERβ activation appears to limit cell proliferation directly or through ERα inhibition, and loss of ERβ has been consistently associated with tumor progression
  • Nathan Goodyear on 21 Aug 13
     
    High aromatase activity and ER alpha expression/signaling associated with prostate disease.
Nathan Goodyear

Nutritional Modulation of Insulin Resistance - 0 views

www.hindawi.com/...424780

macronutrient macronutrients nutrition insulin resistance glucose protein carbohydrates metabolism fats

shared by Nathan Goodyear on 21 Oct 13 - No Cached
  • Five branched chain and aromatic amino acids (isoleucine, leucine, valine, tyrosine, and phenylalanine) showed significant associations with future diabetes
  • there is increasing evidence that longer term high-protein intake may have detrimental effects on insulin resistance [68, 117–123], diabetes risk [69], and the risk of developing cardiovascular disease
  • high-protein and the high GI diets significantly increased markers of low-grade inflammation
  • ...5 more annotations...
  • significant and clinically relevant worsening of insulin sensitivity with an isoenergetic plant-based high-protein diet
  • healthy humans that are exposed to amino acid infusions rapidly develop insulin resistance
  • longer term high-protein intake has been shown to result in whole-body insulin resistance [68, 118], associated with upregulation of factors involved in the mammalian target of rapamycin (mTOR)/S6K1 signalling pathway [68], increased stimulation of glucagon and insulin within the endocrine pancreas, high glycogen turnover [118] and stimulation of gluconeogenesis [68, 118].
  • it was recently shown in a large prospective cohort with 10 years followup that consuming 5% of energy from both animal and total protein at the expense of carbohydrates or fat increases diabetes risk by as much as 30% [69]. This reinforces the theory that high-protein diets can have adverse effects on glucose metabolism.
  • Another recent study showed that low-carbohydrate high-protein diets, used on a regular basis and without consideration of the nature of carbohydrates or the source of proteins, are also associated with increased risk of cardiovascular disease [70], thereby indicating a potential link between high-protein Western diets, T2DM, and cardiovascular risk.
  • Nathan Goodyear on 21 Oct 13
     
    macronutrient intake and effect on glucose regulation and thus metabolism.
Nathan Goodyear

Association between endogenous sex steroid hormones and inflammatory biomarkers in US men - 0 views

www.ncbi.nlm.nih.gov/...PMC3812341

low Testosterone Estrogen Estradiol low T Testosterone hormone hormones CRP inflammation SHBG WBC men male

shared by Nathan Goodyear on 28 Apr 15 - No Cached
  • modest statistically significant inverse associations for total and calculated free testosterone, and modest positive associations for total and calculated free estradiol with CRP concentration
  • Estradiol concentrations were also weakly positively associated with WBC count
  • SHBG was weakly inversely associated with WBC
  • ...21 more annotations...
  • An association between testosterone and WBC count was not observed
  • These findings are consistent with the hypothesis that in men higher androgen concentration is anti-inflammatory, and higher estrogen concentration is pro-inflammatory.
  • the probability of elevated CRP concentrations (≥ 3 mg/L) decreased with higher total and calculated free testosterone concentrations, while the probability increased with higher total and calculated free estradiol concentrations
  • there is ample evidence supporting the immunosuppressive effect of androgens
  • The incidence of autoimmune diseases is higher in androgen-deficient men
  • Studies have shown that the induction of hypogonadism in older men is followed by a significant increase in IL-6 concentrations (Khosla et al. 2002), a potent stimulator of inflammation, and that activation of the androgen receptor exerts a direct anti-inflammatory effect
  • It has been suggested that the mechanisms for the immunosuppressive effect of androgens could be either a direct effect on the expression of inflammatory genes (Bellido et al. 1995; Asirvatham et al. 2006), or an indirect effect through inhibition of nuclear factor-kB activation
  • Estradiol is the major biologically active estrogen, and about 80% is formed in adult men from the aromatization of testosterone primarily in the adipose tissue
  • estrogen can stimulate the transcription factor C/EBP-β, which is involved in CRP transcription
  • Most prior cross-sectional studies have observed inverse associations between androgen concentrations and inflammatory biomarkers
  • A recent study in Chinese men showed that lower concentrations of total and calculated free testosterone were associated with higher CRP concentration
  • Data from the Boston Area Community Health Survey also reported inverse associations between testosterone and CRP concentrations
  • Total testosterone was inversely associated with WBC count (Tang et al. 2007; Schneider et al. 2009; Brand et al. 2012), but calculated free testosterone was not associated with WBC
  • The first trial found a decrease in CRP, interleukin-1β (IL-1β), and tumor necrosis factor-α (TNFα) but no changes in IL-6 and IL-10 concentrations between the active treatment and placebo arms
  • the majority of studies in the literature have not observed statistically significant associations between estradiol and inflammatory biomarkers in men, although several of them observed point estimates in the positive direction
  • total testosterone and estradiol compete for binding to SHBG, and seem to have opposite effects on the concentration of inflammatory biomarkers
  • A small randomized controlled trial of estrogen replacement therapy in prostate cancer patients showed an increase in CRP in the active treatment group versus the comparator group
  • Obese men are known to have lower androgen concentrations compared to their normal-weight counterparts
  • The strongest suggestion of an interaction was the inverse association between androstanediol glucuronide and CRP concentrations in obese participants, while the association was positive in the non-obese
  • A recent Chinese cross-sectional study observed stronger inverse associations between total testosterone and CRP concentrations in individuals with a BMI of 27.5 kg/m2 or greater
  • our results suggest that total and calculated free testosterone are modestly inversely associated with CRP concentrations, and that total and calculated free estradiol are modestly positively associated with CRP and WBC
  • Nathan Goodyear on 28 Apr 15
     
    Study results suggest that higher Testosterone and lower Estrogen levels provide anti-inflammatory effects in men.  The inflammatory biomarker assessed here was CRP.  Low total and calculated free Testosterone was associated with an increase in CRP.  In contrast, total and free Estrogen was associated with an increase in CRP.  Estradiol increased WBC count and SHBG was inversely related to WBC count in this study.
Nathan Goodyear

Branched Chain Amino Acid Supplementation for Patients with Cirrhosis | Clinical Correl... - 0 views

www.clinicalcorrelations.org/?p=3544

BCCA branched chain amino acids liver cirrhosis hepatitis amino acids

shared by Nathan Goodyear on 05 Oct 15 - No Cached
  • low level of BCAAs in patients with cirrhosis is hypothesized to be one of multiple factors responsible for development of hepatic encephalopathy
  • supplementation of BCAAs is thought to facilitate ammonia detoxification by supporting synthesis of glutamine, one of the non-branched chain amino acids, in skeletal muscle and in the brain as well as diminishing the influx of AAAs across the blood-brain barrier
  • oral BCAA supplementation is more useful in chronic encephalopathic patients than is parenteral BCAA supplementation in patients with acute encephalopathy
  • ...35 more annotations...
  • malnutrition progressing to cachexia is another common manifestation of cirrhosis
  • Malnutrition can be mitigated with BCAA supplementation
  • Studies show that administration of amino acid formulas enriched with BCAAs can reduce protein loss, support protein synthesis, and improve nutritional status of patients with chronic liver disease
  • Leucine has been shown to be the most effective of the BCAAs because it acts via multiple pathways to stimulate protein synthesis
  • BCAAs metabolites inhibit proteolysis
  • Patients with cirrhosis have both insulin deficiency and insulin resistance
  • BCAAs (particularly leucine) help to reverse the catabolic, hyperglucagonemic state of cirrhosis both by stimulating insulin release from the pancreatic β cells and by decreasing insulin resistance allowing for better glucose utilization
  • Coadministration of BCAAs and glucose has been found to be particularly useful
  • BCAA supplementation improves protein-energy malnutrition by improving utilization of glucose, thereby diminishing the drive for proteolysis, inhibiting protein breakdown, and stimulating protein synthesis
  • Cirrhotic patients have impaired immune defense, characterized by defective phagocytic activity and impaired intracellular killing activity
  • another effect of BCAA supplementation is improvement of phagocytic function of neutrophils and possibly improvement in natural killer T (NKT) cell lymphocyte activity
  • BCAA supplementation may reduce the risk of infection in patients with advanced cirrhosis not only through improvement in protein-energy malnutrition but also by directly improving the function of the immune cells themselves
  • BCAA administration has also been shown to have a positive effect on liver regeneration
  • A proposed mechanism for improved liver regeneration is the stimulatory effect of BCAAs (particularly leucine) on the secretion of hepatocyte growth factor by hepatic stellate cells
  • BCAAs activate rapamycin signaling pathways which promotes albumin synthesis in the liver as well as protein and glycogen synthesis in muscle tissue
  • Chemical improvement with BCAA treatment is demonstrated by recovery of serum albumin and lowering of serum bilirubin levels
  • long-term oral BCAA supplementation was useful in staving off malnutrition and improving survival by preventing end-stage fatal complications of cirrhosis such as hepatic failure and gastrointestinal bleeding
  • The incidence of death by any cause, development of liver cancer, rupture of esophageal varices, or progression to hepatic failure was decreased in the group that received BCAA supplementation
  • Patients receiving BCAA supplementation also have a lower average hospital admission rate, better nutritional status, and better liver function tests
  • patients taking BCAA supplementation report improved quality of life
  • BCAAs have been shown to mitigate hepatic encephalopathy, cachexia, and infection rates, complications associated with the progression of hepatic cirrhosis
  • BCAAs make up 20-25% of the protein content of most foods
  • Highest levels are found in casein whey protein of dairy products and vegetables, such as corn and mushrooms. Other sources include egg albumin, beans, peanuts and brown rice bran
  • In addition to BCAAs from diet, oral supplements of BCAAs can be used
  • Oral supplementation tends to provide a better hepatic supply of BCAAs for patients able to tolerate PO nutrition as compared with IV supplementation, especially when treating symptoms of hepatic encephalopathy
  • Coadministration of BCAAs with carnitine and zinc has also been shown to increase ammonia metabolism further reducing the encephalopathic symptoms
  • Cirrhotic patients benefit from eating frequent, small meals that prevent long fasts which place the patient in a catabolic state
  • the best time for BCAA supplementation is at bedtime to improve the catabolic state during starvation in early morning fasting
  • A late night nutritional snack reduces symptoms of weakness and fatigability, lowers postprandial hyperglycemia, increases skeletal muscle mass,[25] improves nitrogen balance, and increases serum albumin levels.[26] Nocturnal BCAAs even improve serum albumin in cirrhotic patients who show no improvement with daytime BCAAs
  • Protein-energy malnutrition (PEM), with low serum albumin and low muscle mass, occurs in 65-90% of cases of advanced cirrhosis
  • hyperglucagonemia results in a catabolic state eventually producing anorexia and cachexia
  • BCAAs are further depleted from the circulation due to increased uptake by skeletal muscles that use the BCAAs in the synthesis of glutamine, which is produced in order to clear the ammonia that is not cleared by the failing liver
  • patients with chronic liver disease, particularly cirrhosis, routinely have decreased BCAAs and increased aromatic amino acids (AAAs) in their circulation
  • Maintaining a higher serum albumin in patients with cirrhosis is associated with decreased mortality and improved quality of life
  • the serum BCAA concentration is strongly correlated with the serum albumin level
  • Nathan Goodyear on 05 Oct 15
     
    great review of cirrhosis and BCCA supplementation.
Nathan Goodyear

Branched-chain amino acids in liver diseases - 0 views

www.ncbi.nlm.nih.gov/...PMC3837260

BCAA branched chain amino acids liver cirrhosis disease

shared by Nathan Goodyear on 05 Oct 15 - No Cached
  • Serum concentrations of BCAAs are decreased, while the concentrations of the aromatic amino acids (AAAs) phenylalanine and tyrosine are increased, in patients with advanced liver diseases, resulting in a low ratio of BCAAs to AAAs, a ratio called the Fischer ratio
  • BCAAs were reported to stimulate the production of hepatocyte growth factor
  • a simplified Fischer ratio, the BCAA to tyrosine ratio (BTR), has been reported useful for predicting serum albumin concentration one year later
  • ...10 more annotations...
  • BCAA supplementation was shown to delay the progression of CCl4-induced chronic liver injury in a rat model by reducing hepatic apoptosis
  • BCAAs promoted hepatocyte regeneration in a rat model of hepatectomy
  • BCAA supplementation for advanced cirrhotic patients improves nutritional status and quality of life
  • BCAAs activate mTOR and subsequently increase the production of eukaryotic initiation factor 4E-binding protein-1 and ribosomal protein S6 kinase, which upregulate the synthesis of albumin
  • BCAAs were shown to improve homeostasis model assessment scores for insulin resistance (HOMA-IR) and beta cell function (HOMA-%B) in patients with chronic liver disease, indicating that BCAAs can ameliorate insulin resistance
  • Several clinical trials have suggested that BCAA supplementation improves the prognosis of cirrhotic patients
  • A low Fischer ratio has been associated with hepatic encephalopathy
  • Treatment with BCAAs may therefore have a beneficial effect on patients with hepatic encephalopathy mainly by compensating decreased ratio of BCAAs to AAAs, but not by reducing serum ammonia levels
  • Two randomized studies also showed that BCAAs did not clearly prevent HE in patients with advanced cirrhosis, although BCAAs prevented the progression of hepatic failure
  • a systematic review with meta-analyses on the effect of oral BCAAs for the treatment of HE was published[66]. The review has revealed that supplementation of oral BCAAs in cirrhotic patients inhibits the manifestation of HE, especially in patients with overt HE rather than those with minimal HE, but showed no effect on the survival of those patients[66]. Thus, oral administration of BCAAs is the treatment of choice in cirrhotic patients with HE
  • Nathan Goodyear on 05 Oct 15
     
    good review of BCAA and liver disease: both mechanisms and therapy.
Nathan Goodyear

The multitude and diversity of environmental carci... [Environ Res. 2007] - PubMed result - 0 views

www.ncbi.nlm.nih.gov/...17692309

environmental carcinogens

shared by Nathan Goodyear on 28 Mar 11 - No Cached
  • Of major concerns are: outdoor air pollution by carbon particles associated with polycyclic aromatic hydrocarbons; indoor air pollution by environmental tobacco smoke, formaldehyde and volatile organic compounds such as benzene and 1,3 butadiene, which may particularly affect children, and food pollution by food additives and by carcinogenic contaminants such as nitrates, pesticides, dioxins and other organochlorines. In addition, carcinogenic metals and metalloids, pharmaceutical medicines and cosmetics may be involved
  • Nathan Goodyear on 28 Mar 11
     
    diversity of environmental carcinogens
Nathan Goodyear

Leptin and Androgens in Male Obesity: Evidence for Leptin Contribution to Reduced Andro... - 0 views

press.endocrine.org/...jcem.84.10.6082

obesity leptin low T low Testosterone Testosterone low T leydig cells LH leutenizing hormone men male hormones hormone

shared by Nathan Goodyear on 04 Sep 14 - No Cached
  • in male obesity basal and LH-stimulated androgen levels are reduced and inversely correlated with circulating leptin
  • functional leptin receptors are present in rodent Leydig cells
  • it is conceivable that in males high leptin concentrations may have a direct inhibitory effect(s) on Leydig cell function.
  • ...18 more annotations...
  • insulin is an important inhibitor of the synthesis of SHBG
  • no correlation between leptin and SHBG levels
  • SHBG reduction in obesity is a minor determinant of lowered androgen levels
  • SHBG can explain only up to 3% of the correlation
  • testicular T de novo production is impaired in obese men and that leptin seems to be the best hormonal predictor of this blunted response to LH stimulation
  • The low basal 17-OH-P levels found in massively obese men are consistent with a global impairment of Leydig cell steroidogenic function in this group of subjects.
  • These findings indicate that obese men have a FM-related defect in the enzymatic conversion of 17-OH-P to T, which is revealed by hCG stimulation.
  • Other studies have investigated the adrenal function in male obesity and have shown that basal cortisol and 17-OH-progesterone levels tend to decrease with the increase in the degree of obesity
  • High E2 can inhibit the expression and activity of the 17,20-lyase and may be responsible for this steroidogenic lesion
  • However, stimulated E2 levels were not higher in the obese than in controls, excluding the fact that the lower androgen response was due to an increased aromatization of T to E2 and that estrogens have a major role in the observed defect of 17,20-lyase activity in obese men.
  • the percentage increase in the 17-OH-progesterone to T molar ratio paralleled the increase in leptin levels of obese men
  • Multiple regression analysis indicated that the best hormonal predictor of the obesity-related reduction in T and FT basal levels and androgen changes after hCG stimulation was serum leptin concentration
  • insulin has no negative influences on androgen production in obese men
  • insulin is known to have stimulatory actions on T production that have been demonstrated in obese and normal weight men (57) and in Leydig cells in culture
  • the negative correlation between insulin and basal T can be partly explained by the inhibitory action of insulin on SHBG production
  • hypogonadal men have higher circulating leptin levels compared with hypogonadal patients under effective androgen substitution therapy
  • The impaired androgen response to LH stimulus was due to a defect in the enzymatic conversion of 17-OH-progesterone to T, which was disclosed by a leptin-related increase in 17-OH-progesterone to T ratio
  • Estrogens, which are inhibitory modulators of LH pulsatility and bioactivity
  • Nathan Goodyear on 04 Sep 14
     
    Leptin appears to be a good marker of low Testosterone.  This study proposes that the mechanism of action is potentially 2 fold: first, a decrease in LH release by leptin (kisspeptin?) and 2nd, a directed decrease in Testosterone production by the leydig cells in the testes.
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