Female leptin

[Guest guest]

Hi All,

Anorexia nervosa is discussed regarding the role of leptin, but the condition is

associated with CR, albeit not the ON aspect of CRON. Mental conditions are

also

implicated in the high death rate among those with anorexia nervosa.

Not yet in Medline for its abstract and now pdf-available, is the below review,

for

which is shown the citation, abstract and some excerpts of the 12 page article.

L Chan and Christos S Mantzoros

Role of leptin in energy-deprivation states: normal human physiology and

clinical

implications for hypothalamic amenorrhoea and anorexia nervosa • REVIEW ARTICLE

Lancet 9479, 2005, 74-85

Leptin is an adipocyte-secreted hormone that plays a key part in energy

homoeostasis. Advances in leptin physiology have established that the main role

of

this hormone is to signal energy availability in energy-deficient states.

Studies in

animals and human beings have shown that low concentrations of leptin are fully

or

partly responsible for starvation-induced changes in neuroendocrine axes,

including

low reproductive, thyroid, and insulin-like growth factor (IGF) hormones.

Disease

states such as exercise-induced hypothalamic amenorrhoea and anorexia nervosa

are

also associated with low concentrations of leptin and a similar spectrum of

neuroendocrine abnormalities. We have recently shown in an interventional,

proof-of-concept study that leptin can restore ovulatory menstrual cycles and

improve reproductive, thyroid, and IGF hormones and bone markers in hypothalamic

amenorrhoea. Further studies are warranted to establish the safety and

effectiveness

of leptin for the infertility and osteoporosis associated with hypothalamic

amenorrhoea, and to clarify its role in anorexia nervosa.

.... Leptin was identified as the hormone whose absence resulted in morbid

obesity in

the ob/ob mouse,1 thus acquiring its name from the Greek word “leptos” (thin).

.... acute caloric deprivation for 2–3 days results in a large decrease in leptin

concentrations to roughly 20–30% of baseline, before major changes in bodyweight

or

fat mass have arisen.4 and 9

.... Leptin: hormone for feast or famine?

.... low leptin concentrations are important in signalling energy deficit to the

hypothalamic-pituitary axes, whereas high leptin concentrations in obesity are

associated with resistance to the catabolic effect of leptin to suppress

appetite

and heighten energy expenditure (figure 1).

.... Hypothalamic-pituitary-growth hormone-IGF-1 axis

.... Pathophysiology of leptin in energy deprivation states

.... women with hypothalamic amenorrhoea ... might not meet the criteria for

anorexia

nervosa with psychiatric pathology of disturbed body image and fear of eating

(see

below), but this type of restrictive eating pattern, particularly fat

restriction

(albeit less severe than anorexia nervosa), can result in subclinical

nutritional

deficits that are relevant to the low fat mass and, especially, the low leptin

concentrations associated with this condition. Thus, these women can be judged

to

have energy deficit as well, which is related to decreased energy intake with or

without increased energy expenditure. Consistent with this notion, non-athletic

women with this condition have an array of neuroendocrine and metabolic

abnormalities similar to women with exercise-induced amenorrhoea, including

decreased gonadotropin-releasing hormone pulsatility and oestradiol

concentrations,

lower thyroid hormone concentrations, increased secretion of growth hormone with

decreased IGF-1, and higher cortisol concentrations.61, 64, 65, 69, 73, 79 and

83

.... studies are warranted to establish the ideal dose and duration of r

metHuLeptin

necessary to restore reproductive and other neuroendocrine function without

inducing

an undesirable degree of weight loss in women who are already lean.

.... Osteoporosis is a very common complication of anorexia nervosa, affecting

more

than 50% of female patients

.... Central administration of leptin causes bone loss in mice through the

sympathetic nervous system,139 and 140 a finding that might not be directly

applicable to human beings since leptin does not activate this system.4

.... The only treatment presently available for women who are not interested in

fertility is oestrogen, which has side-effects and does not address other

neuroendocrine abnormalities or the underlying infertility.

.... need to determine the safety and effectiveness of r-metHuLeptin for

restoring

reproductive function and improving bone metabolism in women with hypothalamic

amenorrhoea and also to establish the role of r-metHuLeptin in other low-leptin

states such as anorexia nervosa. If future studies confirm the initial data,

r-metHuLeptin could prove a better treatment for hypothalamic amenorrhoea by

directly addressing the underlying pathophysiology.

.... JLC and CSM have received honoraria from Amgen, which has provided some

funding

for the study of r-metHuLeptin for hypothalamic amenorrhoea.

Al Pater, PhD; email: old542000@...

__________________________________________________

[Guest guest]

> Studies in

> animals and human beings have shown that low concentrations of

leptin are fully or

> partly responsible for starvation-induced changes in neuroendocrine

axes, including

> low reproductive, thyroid, and insulin-like growth factor (IGF)

hormones.

Although this article is obviously going to highlight the pathologic

changes associted with " starvation " , I think it is worth pointing out

that the recent Lancet article associating " obesity " with shortened

telomeres *actually* associated " higher leptin " with shortened

telomeres, *not* BMI.

=-=-=-=--==-=-=-=-

http://www.newscientist.com/article.ns?id=dn7514

" Intriguingly, the link between high leptin concentrations and

telomere shortening was even stronger than the link with obesity, as

measured by the body mass index. Leptin is an appetite-inhibiting

hormone, but obese people are resistant to it and have higher than

normal levels. "

==-=-=-==-=-=-=-=-=-

http://tinyurl.com/7f7fw

http://www.thestandard.com.hk/stdn/std/Weekend/GG02Jp09.html

" In addition, the researchers found that the higher levels of a

hormone in the blood produced by fat cells called leptin, the shorter

the telomeres. "

=-=-=-=-=-=-=-=-=--==

It is presently thought shortened telomeres are a " bad thing " .

" How " bad is open to debate.

T.

pct35768@...