Circulating ghrelin levels in girls with central precocious puberty are reduced during treatment with LHRH analog

Ameliorative effects of aerobic training in girls with precocious puberty: role of leptin and ghrelin

This study was an attempt to examine the changes in serum levels of ghrelin and leptin after 12-weeks of aerobic training and gonadotropin releasing hormone agonist (GnRH) treatment in girls with central precocious puberty. Thirty girls (6-8 years old) with precocious puberty who had received Triptorelin were randomly divided in two groups (medication and medication + training). Fifteen age-matched healthy girls (without precocious puberty) were also included as the control group. The medication + training group submitted an aerobic training program for 3 days/week with 20-75 min per day and 45-75% of maximum heart rate for 12-weeks. Serum levels of leptin, ghrelin, cholesterol, triglycerides and body mass index (BMI) were determined at baseline and 48 h after the last training session. The results indicated that leptin significantly decreased (p = 0.001) and ghrelin significantly increased (p = 0.001) in the medication + training group but no significant difference was observed in the ghrelin (p = 1) and leptin (p = 0.78) in the medication group. Leptin to ghrelin ratio indicated a decrease in medicine + training group (p = 0.028). Ghrelin were negatively correlated with leptin and BMI. The data indicated that aerobic training increased ghrelin and reduced leptin and leptin to ghrelin ratio but GnRH agonist treatment had no effect on plasma leptin and ghrelin levels.

The Role of the Gastric Hormones Ghrelin and Nesfatin-1 in Reproduction

Ghrelin and nesfatin-1 are enteroendocrine peptide hormones expressed in rat X/A-like and human P/D1cells of the gastric mucosa. Besides their effect on food intake, both peptides are also implicated in various other physiological systems. One of these is the reproductive system. This present review illustrates the distribution of ghrelin and nesfatin-1 along the hypothalamus–pituitary–gonadal (HPG) axis, their modulation by reproductive hormones, and effects on reproductive functions as well as highlighting gaps in current knowledge to foster further research.

The Role of the Gastric Hormones Ghrelin and Nesfatin-1 in Reproduction

Ghrelin and nesfatin-1 are enteroendocrine peptide hormones expressed in rat X/A-like and human P/D1cells of the gastric mucosa. Besides their effect on food intake, both peptides are also implicated in various other physiological systems. One of these is the reproductive system. This present review illustrates the distribution of ghrelin and nesfatin-1 along the hypothalamus-pituitary-gonadal (HPG) axis, their modulation by reproductive hormones, and effects on reproductive functions as well as highlighting gaps in current knowledge to foster further research.

The Role of the Gastric Hormones Ghrelin and Nesfatin-1 in Reproduction

Ghrelin and nesfatin-1 are enteroendocrine peptide hormones expressed in rat X/A-like and human P/D1cells of the gastric mucosa. Besides their effect on food intake, both peptides are also implicated in various other physiological systems. One of these is the reproductive system. This present review illustrates the distribution of ghrelin and nesfatin-1 along the hypothalamus–pituitary–gonadal (HPG) axis, their modulation by reproductive hormones, and effects on reproductive functions as well as highlighting gaps in current knowledge to foster further research.

Short-term effects of gonadotropin-releasing hormone analogue treatment on leptin, ghrelin and peptide YY in girls with central precocious puberty

OBJECTIVES

To determine appetite-regulating hormone levels in girls with central precocious puberty (CPP) before and after 20 weeks of gonadotropin-releasing hormone analogue (GnRH-A) treatment.

METHODS

Eighteen newly diagnosed CPP girls were enrolled. Body composition measured by bioelectrical impedance analysis and GnRH-A test were performed with fasting serum leptin, ghrelin and peptide YY (PYY) measurements at baseline (before) and after 20 weeks of GnRH-A treatment.

RESULTS

Following GnRH-A treatment, all patients had prepubertal gonadotropin and estradiol levels. Mean (SD) fat mass index (FMI) was significantly increased from 4.5 (1.7) to 5.0 (1.8) kg/m² after treatment. Also, median (IQR) serum leptin level was significantly increased from 6.9 (4.2-8.6) to 7.4 (5.3-13.1) ng/mL. FMI had a positive correlation with serum leptin level (r=0.64, p=0.004). In contrast, no significant changes of serum ghrelin and PYY levels were observed.

CONCLUSIONS

Decreased estrogen following short-term GnRH-A treatment in CPP girls may cause an increase in appetite and consequently an elevation of FMI. Increased serum leptin may be a result of having increased FMI secondary to an increase in appetite.

Plasma kisspeptin and ghrelin levels in puberty variant cases

BACKGROUND

The aim of this study was to determine the serum levels of kisspeptin and ghrelin (GAH), as well as the relationship of these two peptides with each other in premature thelarche (PT) and premature adrenarche (PA) cases and to investigate the possibility of using these peptides as markers in the differentiation of puberty disorders.

METHODS

A PT group aged 1-8 years (n = 40), a PA group aged 1-9 years (n = 23, female/male = 20/3) and control groups consistent with each of the previous groups in terms of age and gender were created for the study. Kisspeptin and ghrelin levels were measured with ELISA methods from blood samples drawn while fasting in the morning.

RESULTS

When the PT group was compared with the controls, the plasma kisspeptin levels of the cases were significantly higher than the control group (165.47 ± 15.45 pmol/L, 96.82 ± 12.33 pmol/L, p = 0.005, respectively). Kisspeptin levels in the PA group did not show a difference with the control group (121.36 ± 17.99 pmol/L, 95.52 ± 11.54 pmol/L, p = 0.249, respectively). No significant difference could be found when GAH levels in the PT and PA groups were compared with controls. No significant correlation was found between kisspeptin and GAH levels in the PT and PA groups.

CONCLUSIONS

Our results indicate that kisspeptin plays an important role in the PT, but GAH is not associated with puberty disorders.

Changes in body mass index during gonadotropin-releasing hormone agonist treatment for central precocious puberty and early puberty

Gonadotropin-releasing hormone agonists (GnRHa) have been widely used for decades to treat patients with central precocious puberty (CPP). Several studies have investigated changes in body composition in patients with CPP following GnRHa treatment, but the results are inconsistent. The aim of this study was to investigate changes in body mass index (BMI) in children treated with GnRHa for 2 years. We also assessed whether BMI affects treatment outcomes. This study included 383 girls (214 girls with central precocious puberty and 169 girls who underwent early puberty) treated with depot leuprolide acetate monthly for at least 2 years. We analyzed changes in BMI standard deviation score (SDS). Furthermore, blood luteinizing hormone (LH) levels were determined 30 min after depot leuprolide acetate administration every 6 months to evaluate adequate suppression of the hypothalamic-pituitary-gonadal axis. Pretreatment mean BMI SDS values were 0.07 ± 0.69, 1.29 ± 0.16, and 1.95 ± 0.32 in the normal weight, overweight, and obese subjects, respectively. Mean BMI SDS values after 2 years of treatment increased significantly only in normal weight children (0.07 ± 0.69 vs. 0.25 ± 0.73, P < 0.001). LH levels 30 min after leuprolide injection after 2 years of treatment were not different among normal weight, overweight, and obese subjects. Although the difference in BMI SDS was relatively small, it standard deviation score increased significantly after 2 years of treatment in normal weight girls with early pubertal development.

Integrating GHS into the Ghrelin System

Oligopeptide derivatives of metenkephalin were found to stimulate growth-hormone (GH) release directly by pituitary somatotrope cells in vitro in 1977. Members of this class of peptides and nonpeptidyl mimetics are referred to as GH secretagogues (GHSs). A specific guanosine triphosphatate-binding protein-associated heptahelical transmembrane receptor for GHS was cloned in 1996. An endogenous ligand for the GHS receptor, acylghrelin, was identified in 1999. Expression of ghrelin and homonymous receptor occurs in the brain, pituitary gland, stomach, endothelium/vascular smooth muscle, pancreas, placenta, intestine, heart, bone, and other tissues. Principal actions of this peptidergic system include stimulation of GH release via combined hypothalamopituitary mechanisms, orexigenesis (appetitive enhancement), insulinostasis (inhibition of insulin secretion), cardiovascular effects (decreased mean arterial pressure and vasodilation), stimulation of gastric motility and acid secretion, adipogenesis with repression of fat oxidation, and antiapoptosis (antagonism of endothelial, neuronal, and cardiomyocyte death). The array of known and proposed interactions of ghrelin with key metabolic signals makes ghrelin and its receptor prime targets for drug development.

Gender difference of circulating ghrelin and leptin concentrations in chronic Helicobacter pylori infection

BACKGROUND

Both ghrelin and leptin are important appetite hormones secreted from the stomach. We examined whether demographic background, Helicobacter pylori infection, or its related gastritis severity could be associated with circulating ghrelin and leptin levels.

METHODS

This study prospectively enrolled 341 dyspeptic patients (196 females, 145 males), who had received endoscopy to provide the gastric specimens over both antrum and corpus for histology reviewed by the updated Sydney's system. The fasting blood sample of each patient was obtained for total ghrelin and leptin analysis.

RESULTS

Without H. pylori infection, there were similar ghrelin levels between female and male patients. In the H. pylori-infected patients, the males had lower plasma ghrelin levels than females (1053 vs. 1419 pg/mL, p < .001). Only in males, not in females, the H. pylori infection and its related acute and chronic inflammation scores were significantly associated with a lower ghrelin level (p < or = .04). The multivariate regression disclosed that only the chronic inflammation score independently related to a lower ghrelin level. Only in males, the ghrelin levels ranked in a downward trend for the gastritis feature as with limited-gastritis, with antrum-predominant gastritis, and with corpus-gastritis (1236, 1101, and 977 pg/mL). Leptin level was not related to H. pylori-related gastritis, but positively related to body mass index.

CONCLUSION

There should be a gender difference to circulating total ghrelin levels, but not leptin levels, in response to H. pylori infection and its related chronic gastritis.

Changes of ghrelin following oral glucose tolerance test in obese children with insulin resistance

AIM: To characterize changes in ghrelin levels in response to oral glucose tolerance test (OGTT) and to correlate changes in ghrelin levels with changes in insulin and glucose following OGTT in Chinese obese children of Tanner I and II stage with insulin resistance.

METHODS: 22 obese children with insulin resistance state were divided into four groups according to their Tanner stage and gender: boys of Tanner I(BT-I), boys of Tanner II (BT-II), girls of Tanner I(GT-I), girls of Tanner II (GT-II). Ghrelin, insulin and glucose were measured at 0, 30, 60 and 120 min following OGTT. The control children with normal BMI were divided into control boys of Tanner I (CBT-I, n = 6), control boys of Tanner II (CBT-II, n = 5), control girls of Tanner I (CGT-I, n = 6), control girls of Tanner II (CGT-II, n = 5). Fasting serum ghrelin levels were analyzed.

RESULTS: Ghrelin levels were lower in obese groups. Ghrelin levels of control group decreased in Tanner II stage (CGT-I vs CGT-II t = -4.703, P = 0.001; CBT-I vs CBT-II t = -4.794, P = 0.001). Basal ghrelin levels in BT-II decreased more significantly than that in BT-Igroup (t = 2.547, P = 0.029). Ghrelin levels expressed a downward trend after OGTT among obese children. The decrease in ghrelin levels at 60 min with respect to basal values was 56.9% in BT-I. Ghrelin concentrations at 0 min correlated directly with glucose level at 0 min in BT-I (r = 0.898, P = 0.015). There wasn’t a significant correlation of ghrelin changes with glucose changes and insulin changes during OGTT in obese children with insulin resistance.

CONCLUSION: In conclusion, in obese children with insulin resistance, ghrelin levels decreased with advancing pubertal stage. Ghrelin secretion suppression following OGTT was influenced by gender and pubertal stage. Baseline ghrelin levels and ghrelin suppression after OGTT did not significantly correlate with the degree of insulin resistance and insulin sensitivity.

Metabolic fuel and clinical implications for female reproduction

Reproduction is a physiologically costly process that consumes significant amounts of energy. The physiological mechanisms controlling energy balance are closely linked to fertility. This close relationship ensures that pregnancy and lactation occur only in favourable conditions with respect to energy. The primary metabolic cue that modulates reproduction is the availability of oxidizable fuel. An organism's metabolic status is transmitted to the brain through metabolic fuel detectors. There are many of these detectors at both the peripheral (e.g., leptin, insulin, ghrelin) and central (e.g., neuropeptide Y, melanocortin, orexins) levels. When oxidizable fuel is scarce, the detectors function to inhibit the release of gonadotropin-releasing hormone and luteinizing hormone, thereby altering steroidogenesis, reproductive cyclicity, and sexual behaviour. Infertility can also result when resources are abundant but food intake fails to compensate for increased energy demands. Examples of these conditions in women include anorexia nervosa and exercise-induced amenorrhea. Infertility associated with obesity appears to be less related to an effect of oxidizable fuel on the hypothalamic-pituitary-ovarian axis. Impaired insulin sensitivity may play a role in the etiology of these conditions, but their specific etiology remains unresolved. Research into the metabolic regulation of reproductive function has implications for elucidating mechanisms of impaired pubertal development, nutritional amenorrhea, and obesity-related infertility. A better understanding of these etiologies has far-reaching implications for the prevention and management of reproductive dysfunction and its associated comorbidities.