02-28-2008, 03:32 PM
a surge of GH due to surge of GNRH...but it depends...
Leptin has been proposed as the hormone responsible for the initiation and progression of puberty. Leptin is
produced largely in adipocytes; large fat cells produce more leptin than do small ones, and serum leptin
concentrations are highly correlated with body fat content. The potential importance of leptin is illustrated
by the observation that mice and rats deficient in leptin fail to undergo pubertal development, whereas the
administration of leptin to such animals results in pubertal onset [29]. Furthermore, higher serum leptin
concentrations in girls are associated with increased body fat and an earlier onset of puberty [30]. In this
study, a 1 ng/mL increase in serum leptin lowered the age at menarche by 1 month, and a gain in body fat
of 1 kg lowered the timing of menarche by 13 days. (See "Physiology of leptin").
Leptin appears to be one of several factors that influence the maturation of the gonadotropin-releasing
hormone (GnRH) pulse generator, probably as a signal of the availability of metabolic fuel [31]. Serum leptin
concentrations increase immediately before puberty in both genders, but differ after the initiation of
puberty.
In males, serum leptin falls after the onset of puberty, returning to baseline 30 to 40 months later [ 32].
In females, leptin values rise throughout puberty, and may be influenced by many factors. In one study,
leptin values in pubertal girls were correlated with the sum of skinfolds (abdominal subcutaneous more than
abdominal visceral more than peripheral subcutaneous fat), as well as serum free testosterone and free
estrogen; these three factors accounted for 74 percent of the variance in leptin levels [ 33].
uptodate 2008
Leptin has been proposed as the hormone responsible for the initiation and progression of puberty. Leptin is
produced largely in adipocytes; large fat cells produce more leptin than do small ones, and serum leptin
concentrations are highly correlated with body fat content. The potential importance of leptin is illustrated
by the observation that mice and rats deficient in leptin fail to undergo pubertal development, whereas the
administration of leptin to such animals results in pubertal onset [29]. Furthermore, higher serum leptin
concentrations in girls are associated with increased body fat and an earlier onset of puberty [30]. In this
study, a 1 ng/mL increase in serum leptin lowered the age at menarche by 1 month, and a gain in body fat
of 1 kg lowered the timing of menarche by 13 days. (See "Physiology of leptin").
Leptin appears to be one of several factors that influence the maturation of the gonadotropin-releasing
hormone (GnRH) pulse generator, probably as a signal of the availability of metabolic fuel [31]. Serum leptin
concentrations increase immediately before puberty in both genders, but differ after the initiation of
puberty.
In males, serum leptin falls after the onset of puberty, returning to baseline 30 to 40 months later [ 32].
In females, leptin values rise throughout puberty, and may be influenced by many factors. In one study,
leptin values in pubertal girls were correlated with the sum of skinfolds (abdominal subcutaneous more than
abdominal visceral more than peripheral subcutaneous fat), as well as serum free testosterone and free
estrogen; these three factors accounted for 74 percent of the variance in leptin levels [ 33].
uptodate 2008