I forgot this:
Horm Res. 1998;49(5):240-6.
Relation of race, age, and sex hormone differences to serum leptin
concentrations in children and adolescents.
Ambrosius WT, Compton JA, Bowsher RR, Pratt JH.
Department of Medicine, Indiana University School of Medicine, and the VA
Medical Center Indianapolis, USA.
We explored the effects of race, age, and sex hormones on the serum leptin
concentrations in 203 white and 88 black children and adolescents (ages
9.3-20.5 years). A significant sex by race interaction on serum leptin
levels (p = 0.0301) was observed with lower serum leptin concentrations,
adjusted for subscapular thickness and age, in black boys than in white
boys. Girls had serum leptin levels that were on average 2.15 times those of
boys (p < 0.0001). There was an age by sex interaction (p < 0.0001) with
serum leptin concentrations decreasing in boys but not in girls with age. A
strongly inverse relationship of serum testosterone levels with serum leptin
levels in boys (p = 0.0067) appeared to explain this effect of age. In
conclusion, the serum leptin concentration is slightly lower in black boys.
A higher testosterone level in boys appears to account for an age-related
decline in serum leptin in boys and the overall lower levels in boys than in
"James Michael Howard" <jmhoward at arkansas.net> wrote in message
news:4lqtov8re126n89nnb5trq1pf8i0997gu6 at 4ax.com...
> On 16 Oct 2003 16:13:06 GMT, "Dag Stenberg"
> <dag.stenberg at nospam.helsinki.fi.invalid> wrote:
>> >James Michael Howard <jmhoward at arkansas.net> wrote:
> >> Mr. Stenberg, thank you for your response. What you presented makes
> >> However, I wish to push the explanation back just a step. Testosterone
> >> melatonin, which produces sleep. Melatonin suppresses leptin.
> >> testosterone reduces leptin itself and reduces melatonin which reduces
> >1. Where do you find any evidence that testosterone reduces melatonin?
> >Melatonin does reduce testosterone in rats, but the other way around??
> >2. Melatonin is a weak and unreliable hypnotic, and its role in
> >physiological sleep regulation is in doubt.
> >3. I agree that melatonin reduces leptin in some mammals (like
> >middle-aged rats), but increases leptin in minks.
> >In postmenopausal women, melatonin does not affect leptin levels. I am
> >not aware of other studies of the effect of melatonin on leptin in
> >Dag Stenberg
>> Testosterone reduces melatonin. In treatment of a 14 year-old boy,
> et al., conclude that "These results indicate that circulating
> down-regulates pineal melatonin." (J Pediatr Endocrinol Metab 1995; 8:
> In another study, Luboshitzky, et al., testosterone treatment reduced
> secretion in sex male patients with increased nocturnal melatonin (J
> 1997; 22: 95-101).
>> There is a controversy re melatonin and sleep. I happen to be on the side
> melatonin is involved in sleep: www.anthropogeny.com/physiology.html .
>> Well, you are correct re melatonin and leptin in rats. We will just have
> wait and see.