Leptin Stimulates the Reproductive Male Axis in Rats during Sexual Maturation by Acting on Hypothalamic Excitatory Amino Acids

Oj, Ponzo; Reynoso, Roxana; Rimoldi, Guillermo; Rondina, Dora; Szwarcfarb, Berta; Carbone, Silvia; Scacchi, Pablo; Ja, Moguilevsky

doi:10.1055/s-2005-837525

Cited by 11 publications

(6 citation statements)

References 15 publications

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“…CDGP is a variation of the onset and timing of pubertal development without a defined endocrine abnormality. Recently published results showed that both leptin and ghrelin have a role in GnRH production at different reproductive stages [18,20,21]; they showed opposing effects on pulsatile GnRH secretion [18]. We hypothesized that low leptin and high ghrelin concentrations could be implicated in altering the tempo of puberty in adolescents with CDGP.…”

Section: Discussionmentioning

confidence: 99%

Association of ghrelin and leptin with reproductive hormones in constitutional delay of growth and puberty

El-Eshmawy

Aal

hawary

2010

Reprod Biol Endocrinol

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BackgroundConstitutional delay of growth and puberty (CDGP) is a variation of the onset and timing of pubertal development without a defined endocrine abnormality. Recently published studies indicate that leptin and ghrelin play a role in puberty initiation and progress. They have been implicated in regulation of GnRH secretion, with ghrelin having inhibitory and leptin, facilitatory effects. We hypothesized that elevated ghrelin and reduced leptin concentrations could be implicated in altering the tempo of puberty in adolescents with CDGP. So in the current study we evaluate variations in leptin and ghrelin levels in adolescent boys with CDGP, the relationships between both hormones and reproductive hormones including LH, FSH and testosterone were also evaluated.MethodsThe study enrolled 23 adolescent boys with CDGP and 20 healthy controls matched for age and sex. Weight, height, BMI, testicular volume, bone age, bone age delay, serum FSH, LH, testosterone, leptin and ghrelin were assessed.ResultsAdolescent boys with CDGP had significantly lower leptin and higher ghrelin than normal controls. Leptin was positively correlated with BMI, bone age, testicular volume, FSH, LH and testosterone and negatively correlated with delayed bone age and ghrelin. Ghrelin was negatively correlated with BMI, bone age, testicular volume, FSH, LH and testosterone. With multiple regression analysis BMI, FSH, LH, testosterone and ghrelin remained independently correlated with leptin while BMI, LH and testosterone remained independently correlated with ghrelin.ConclusionElevated serum ghrelin and decreased leptin concentrations and their associations with reproductive hormones may explain the sexual immaturity in adolescent boys with CDGP.

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Section: Discussionmentioning

confidence: 99%

Association of ghrelin and leptin with reproductive hormones in constitutional delay of growth and puberty

El-Eshmawy

Aal

hawary

2010

Reprod Biol Endocrinol

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“…Leptin has facilitatory effects on GnRH secretion and is considered to be an important regulator of GnRH and gonadotrophin secretion. 9,28 Low leptin levels would therefore contribute to a hypogonadal state and low levels of gonadal steroids. It is interesting that in our study, leptin was an independent predictor of E 2 but not of testosterone, and that when fat mass was added to the model, this replaced leptin as an independent predictor of E 2 levels.…”

Section: Discussionmentioning

confidence: 99%

Acylated Ghrelin and Leptin in Adolescent Athletes With Amenorrhea, Eumenorrheic Athletes and Controls: A Cross-Sectional Study

Christo

Cord

Mendes

et al. 2009

Obstetrical &Amp; Gynecological Survey

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Previous reports suggest that adolescent endurance athletes such as gymnasts and swimmers may be at higher risk of amenorrhea (AA) than other adolescent athletes. Neuroendocrine factors that differentiate athletes with AA from eumenorrheic athletes (EA) have been investigated but are not completely understood.Two neuroendocrine peptides, leptin and ghrelin, appear to be involved in regulation of the hypothalamo-pituitarygonadal axis. Low leptin levels and high ghrelin levels have been implicated in the occurrence of amenorrhea in adult athletes. The investigators hypothesized that blood levels of leptin and/or ghrelin could predict levels of gonadal steroids in adolescent athletes and identify which will develop ammenorhea. This cross-sectional study compared the levels of leptin, ghrelin, and gonadal steroids among adolescent athletes with AA, EA, and nonathletic controls at a large urban hospital. The study enrolled 58 adolescent girls, 12-18 years old, including 21 AA, 19 EA and 18 nonathletic controls. There was no history of amenorrhea or menarchal delay in the nonathletic controls. Active ghrelin, leptin, estrogen (E 2 ), and testosterone were measured in fasting blood.The body mass index (BMI) in AA was significantly lower than among EA and controls at baseline (P ϭ 0.003). Log active ghrelin levels were significantly higher in AA compared to the other two groups (P Ͻ 0.0001); the difference was maintained after controlling for BMI Z-scores (P ϭ 0.0007). Leptin levels were lower in AA compared to the other two groups (P Ͻ 0.0001), but did not remain significant after controlling for BMI Z-scores. Total testosterone levels were lower among AA compared to the EA and controls (P ϭ 0.002), and the differences remained significant after controlling for BMI Z-scores (P ϭ 0.03. There was a significant trend for lower E 2 scores among AA than the EA (P ϭ 0.07), but the effect was not significant after controlling for BMI Z-scores. Inverse associations of log active ghrelin with testosterone were noted (P ϭ 0.05), whereas there were positive associations of leptin with testosterone (P ϭ 0.05) and log E 2 (P ϭ 0.01).These data show that ghrelin and leptin are independent predictors of levels of gonadal steroids. The investigators conclude from these findings that lower leptin levels and especially higher ghrelin levels may predict which athletes will develop amenorrhea.

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“…7,9,13,[24][25][26][27] Additionally, leptin and ghrelin showed opposing effects on pulsatile GnRH secretion. 9 Furthermore, obese children have early puberty that could be the effect of high circulating levels of leptin.…”

Section: Discussionmentioning

confidence: 99%

Ghrelin and leptin levels in relation to puberty and reproductive function in patients with beta-thalassemia

Moshtaghi-Kashanian¹,

Razavi²

2009

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OBJECTIVE:Recently published animal studies indicate that leptin and ghrelin play a role in puberty initiation and progress as well as in reproduction. The aim of our study was to evaluate the relation of these two hormones to the pubertal maturity and fertility status in patients with β-thalassemia. DESIGN: Blood levels of leptin, acylated ghrelin and sex hormones were determined in 97 (59 males and 38 females) beta-thalassemic patients, aged 18-23 years and in 50 healthy subjects (27 males and 23 females) matched for age. Body Mass Index (BMI) was also assessed. RESULTS: Besides lower BMI, all the hormones evaluated were significantly lower in β-thalassemic patients compared to controls (p<0.001). Furthermore, the leptin/ghrelin ratio in female patients was lower than the values obtained in the controls (p<0.001). Finally, significant negative correlations (p=0.050) were detected between circulating levels of acylatedghrelin and LH, FSH and sex hormones in female and male patients. CONCLUSIONS: The lower values of leptin and ghrelin in patients with β-thalassemia possibly constitute another hormonal imbalance which may contribute to the phenotype of impaired growth and sexual maturation encountered in these patients. The findings on the ghrelin levels constitute a novel observation.

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Leptin Stimulates the Reproductive Male Axis in Rats during Sexual Maturation by Acting on Hypothalamic Excitatory Amino Acids

Cited by 11 publications

References 15 publications

Association of ghrelin and leptin with reproductive hormones in constitutional delay of growth and puberty

Association of ghrelin and leptin with reproductive hormones in constitutional delay of growth and puberty

Acylated Ghrelin and Leptin in Adolescent Athletes With Amenorrhea, Eumenorrheic Athletes and Controls: A Cross-Sectional Study

Ghrelin and leptin levels in relation to puberty and reproductive function in patients with beta-thalassemia

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