Plasma testosterone levels in Alzheimer and Parkinson diseases

Okun, Michael S.; DeLong, Mahlon R.; Hanfelt, John; Gearing, Maria; Levey, A. I.

doi:10.1212/01.wnl.0000106840.72938.84

Cited by 68 publications

(42 citation statements)

References 16 publications

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“…Similar findings of low testosterone in men with AD have been reported in several (Almeida et al, 2004;Moffat et al, 2004;Paoletti et al, 2004;Rasmuson et al, 2002;Watanabe et al, 2004) but not all (Pennanen et al, 2004) studies. Interestingly, low testosterone has also been linked to several other neurodegenerative diseases, including Parkinson's disease (Okun et al, 2004), vascular dementia (Watanabe et al, 2004), amyotropic lateral sclerosis (Militello et al, 2002), and Huntington's disease (Markianos et al, 2005).…”

Section: Age-related Androgen Depletion and Alzheimer's Diseasementioning

confidence: 99%

Androgen cell signaling pathways involved in neuroprotective actions

Pike

Nguyen

Ramsden

et al. 2008

Hormones and Behavior

114

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As a normal consequence of aging in men, testosterone levels significantly decline in both serum and brain. Age-related testosterone depletion results in increased risk of dysfunction and disease in androgen-responsive tissues, including brain. Recent evidence indicates that one deleterious effect of age-related testosterone loss in men is increased risk for Alzheimer's disease (AD). We discuss recent findings from our laboratory and others that identify androgen actions implicated in protecting the brain against neurodegenerative diseases and begin to define androgen cell signaling pathways that underlie these protective effects. Specifically, we focus on the roles of androgens as (1) endogenous negative regulators of β-amyloid accumulation, a key event in AD pathogenesis, and (2) neuroprotective factors that utilize rapid non-genomic signaling to inhibit neuronal apoptosis. Continued elucidation of cell signaling pathways that contribute to protective actions of androgens should facilitate the development of targeted therapeutic strategies to combat AD and other agerelated neurodegenerative diseases.

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Section: Age-related Androgen Depletion and Alzheimer's Diseasementioning

confidence: 99%

Androgen cell signaling pathways involved in neuroprotective actions

Pike

Nguyen

Ramsden

et al. 2008

Hormones and Behavior

114

View full text Add to dashboard Cite

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“…Several studies have determined that men with AD have reduced levels of endogenous total or bioavailable testosterone (49)(50)(51). AD is characterized by senile plaques and neurofibrillary tangles in the brain.…”

Section: Testosterone Substitution In Men With Cognitive Impairmentmentioning

confidence: 99%

Testosterone and cognitive function: current clinical evidence of a relationship

Beauchet¹

2006

eur j endocrinol

144

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Background: Testosterone levels decline as men age, as does cognitive function. Whether there is more than a temporal relationship between testosterone and cognitive function is unclear. Chemical castration studies in men with prostate cancer suggest that low serum testosterone may be associated with cognitive dysfunction. Low testosterone levels have also been observed in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). This paper reviews the current clinical evidence of the relationship between serum testosterone levels and cognitive function in older men. Methods: A systematic literature search was conducted using PubMed and EMBASE to identify clinical studies and relevant reviews that evaluated cognitive function and endogenous testosterone levels or the effects of testosterone substitution in older men. Results: Low levels of endogenous testosterone in healthy older men may be associated with poor performance on at least some cognitive tests. The results of randomized, placebo-controlled studies have been mixed, but generally indicate that testosterone substitution may have moderate positive effects on selective cognitive domains (e.g. spatial ability) in older men with and without hypogonadism. Similar results have been found in studies in patients with existing AD or MCI. Conclusions: Low endogenous levels of testosterone may be related to reduced cognitive ability, and testosterone substitution may improve some aspects of cognitive ability. Measurement of serum testosterone should be considered in older men with cognitive dysfunction. For men with both cognitive impairment and low testosterone, testosterone substitution may be considered. Large, longterm studies evaluating the effects of testosterone substitution on cognitive function in older men are warranted.

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“…Her ne kadar kontrol grubundaki olguların hipogonadizm semptomları normal popülâsyona göre düşük görünse de Parkinson'lu hastaların semptomları hem kontrol grubuna göre hem de normal popülâsyona göre anlamlı olarak daha yüksektir. Bu çalışma, Parkinson hastalığında AMS-SF'yle semptomların değerlendirildiği literatürdeki bilinen ilk çalışmadır Okun ve arkadaşlarının [30] 68 Parkinson, 50 Alzheimer hastasını değerlendirdiği çalışmalarında Parkinson hastalarının %35'inde toplam testosteron seviyeleri normalin altında çıkmıştır. Ayrıca, kan testosteron seviyelerinin her iki hastalıkta da yaşla beraber düştüğünü ve bu düşüşün her 10 yıl için 65.9 ng/mL olduğunu belirtmişlerdir.…”

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