Preliminary investigation of plasma levels of sex hormones and human growth factor(s), and P300 latency as correlates to cognitive decline as a function of gender

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From: BMC Research Notes(Vol. 2)
Publisher: BioMed Central Ltd.
Document Type: Report
Length: 3,059 words

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Authors: Eric R Braverman [1,2]; Thomas JH Chen [3,4]; Amanda LC Chen [3,4]; Mallory M Kerner [1,2]; Howard Tung [7]; Roger L Waite [6]; John Schoolfield [5]; Kenneth Blum (corresponding author) [1,2,6,8]

Introduction

A review of the literature reveals that sex hormones have often been associated with changes in behavioral and mental abilities. As noted by Craig and Murphy, estrogen may modulate brain function, and acute loss of ovarian hormones increases neuronal membrane breakdown. Additionally, suppression of ovarian function may reduce activation of brain regions that are critical for memory [1]. Other research has shown that estrogen use may improve mood amongst women with postnatal or perimenstrual depression; however, it may contribute to increasing depressive symptoms in women with premenstrual dysphoria [2]. Although it has yet to become widely accepted, research has shown that estrogen replacement therapy may help prevent Alzheimer's dementia [3].

The behavioral effects of the androgens testosterone and dehydroepiandrosterone (DHEA) remain unclear but preliminary reports suggest that their use is associated with improved mood [4, 5]. There is evidence that there is an age-related testosterone depletion associated with the development of Alzheimer disease [6]. At present, there is not enough hard data to support the use of sex hormones and DHEA, the adrenal androgen, for the treatment of depression, cognitive decline or memory deficits.

The GH/insulin-like growth factor-1 (GH/IGF-1) axis is known to be involved in aging of physiological functions including low levels associating with cognitive decline as a function of age [7]. Deficiency of growth hormone (GH), an important regulator of IGF-1, is associated with reduced wellbeing [8]. Furthermore, since plasma IGF-1 levels have been reported to be enhanced by DHEA administration, it has been suggested that IGF-1 may have a role in some of the reported associations between low DHEA sulfate levels and impaired health measures in elderly subjects [9].

Since there is sparse definitive information on hormone plasma levels for measurement of cognitive decline as an age-related process, we decided to investigate this issue.

Methods

Plasma sex and growth hormones (testosterone, DHEA, estrogen, progesterone, GH and IGF-1) were analyzed in both males and females across a wide age range and the results were statistically correlated with an electroencephalograph-obtained event-related potential (P300), whose prolonged latency has been established as an accurate predictor of cognitive and memory decline. The methods employed in this study were previously reported by our laboratory [10]. Subjects also took the Wechsler Memory Scale (WMSIII) and the Test of Variables of Attention (T.O.V.A.), which have been described in our previous work [10].

Subjects

In this large (721 females and 654 males with an age range of 30-93 years) clinically based study, all patients were tested for their response to the P300 event-related potential (ERP) and screened for circulating hormones (testosterone, progesterone, estrogen, dehydroepiandrosterone (DHEA), and growth hormones IGF-1 and IGFBP-3). Mean [+ -] standard deviation of age for females was 57.4 [+ -] 15.1 and 55.8 [+ -] 14.5 for males.

Criteria for study inclusion

The patients had at least one P300...

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Gale Document Number: GALE|A204574259