Nicotine, DHEA, brain and fat metabolism and ageing

Smokers have substantially higher serum levels of dehydroepiandrosterone (DHEA), its sulfate (DHEAS) and androstenedione (Hautanen et al., 1993; Field et al., 1994; Baron et al., 1995; al'Absi et al., 2003). There is also extensive evidence that cigarette smoking acutely increases circulating cortisol levels (Winternitz & Quillen, 1977; Wilkins et al., 1982; Seyler et al., 1984).
[link to www.medscape.com]

Individuals of low DHEA would seek drugs that increase DHEA. Schizophrenics would be more prone to have significantly low DHEA. It is known that nicotine significantly increases the reserve form of DHEA, DHEA sulfate. DHEA is made from DHEAS.
[link to www.dheausa.com]

Fat Loss Supplements Update DHEA, Nicotine and Usnic Acid
DHEA Cuts Abdominal Fat
DHEA is a naturally occurring steroid hormone produced by the adrenal glands.
Before being secreted into the blood, most of the DHEA is sulfated to form dehydroepiandosterone sulfate (DHEAS), which is the dominant steroid in the blood in most mammals, including humans. As illustrated in Figure 1, the levels of DHEAS in men and women decline as they get older.
Fifty-six elderly men and women (aged 65-78 years) with age-related decreases in DHEA-levels
participated in this randomized, double-blind, placebo controlled trial.
Results indicated that DHEA supplementation compared with placebo induced
significant decreases in abdominal fat (-13 cm2 versus +3 cm2) and subcutaneous fat (-13 cm2 versus +2 cm2). DHEA also improved insulin sensitivity and increased blood levels of insulin-like growth factor (IGF-1). According to the authors, “These findings provide evidence that DHEA replacement therapy may partially reverse the aging-related accumulation of abdominal fat in elderly people with low [blood] levels of DHEAS… Large studies, however, will be needed to verify our findings.”
Dr. Anna Jessen and colleagues at the Royal Veterinary and Agricultural University in Denmark examined the acute thermogenic (heat producing) effects of chewing gum containing different doses of nicotine and caffeine. This well-controlled study included 12 healthy, normal-weight men; energy expenditure was measured before and 2.5 hours after subjects chewed the gum. Interestingly, the results indicated that one milligram of nicotine has a pronounced thermogenic effect, which is increased by about 100 percent when it’s combined with 100 milligrams of caffeine. Also, no side effects were reported with the gums that contained one milligram of nicotine with 50 or 100 milligrams of caffeine.
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There is a theory that DHEA (dihydroepiandrosterone), an adrenal hormone, conserves tissues and prevents ageing. Significantly higher levels of DHEA are found in meditators, some equivalent to people 5-10 years their junior.
[link to www.lotushealth.com.au]

Jeanne Louise Calment (21 February 1875 – 4 August 1997)[2] was a French supercentenarian who had the longest confirmed human lifespan in history, living to the age of 122 years, 164 days.
Calment smoked from the age of 21 (1896) to 117 (1992).
[link to en.wikipedia.org]

My work suggest that all tissues require DHEA for optimal transcription of genes. Also, all tissues compete for the available DHEA. I think the brain is able to absorb more DHEA than any other tissue. Hence, increased DHEA results in increased transcription in the brain, compared to other tissues. Brain is characterized by high metabolic activity and exhibits two to three times the transcriptional activity of other tissues. (J. Neurochem. 1991; 56: 812). This means that the "dip" in available DHEA between the peak from birth to early childhood and adrenarche is due to use of DHEA by the developing brain. As the brain finishes its development, the available (measurable) levels of DHEA increase.
As the brain increases in size, measurable levels of DHEA decline. The brain is using the DHEA. This also follows the size of the denditions. Lots of DHEA means large teeth.
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