[Urinary tract infections: review of the case records of the 5-year-old population of Novara]

AIM

A feverish high temperature is the symptom that most frequently leads families to take their children to a Pediatric First Aid unit. In the differential diagnosis of the causes of hyperpyrexia the presence of infections of the genito-urinary tract have to be excluded. Infections of the urinary ways are often the cause of high temperatures in infancy, particularly during the 1st year of life; early identification at the moment of examination at the Paediatric First Aid clinic of patients with infections of the urinary ways makes it possible to prevent the onset of renal complications. We carried out a retrospective study with the purpose of evaluating the incidence of infections of the urinary ways and their complications in paediatric patients who had come to the First Aid unit for hyperpirexia and were later hospitalised after examination of the urine revealed and infection of the urinary ways.

METHODS

The study was carried out by consulting the registers listing arrivals at the First Aid unit and the subsequent discharge diagnosis. We then consulted the clinical records of patients who required admission to our Paediatrics Clinic arter the first aid examination.

RESULTS

Re-reading the registers of examination carried out and the clinica records of hospitalised patients there emerged an increase in the observation of this pathology, diagnosed at the moment of the First Aid examination by means of rapid tests and thereafter assessed by haematochemical and radiological tests.

CONCLUSIONS

In our opinion this increase could be attributed to the greater attention paid to diagnosing the causes of fever of apparently unknown origin.

Genetic defects in GH synthesis and secretion

Growth hormone (GH) is a multifunctional hormone produced in the anterior pituitary that promotes postnatal growth of skeletal and soft tissues. GH secretion and release are complex phenomena depending on several intrinsic and extrinsic factors modulating the release of two hypothalamic hormones, GH releasing hormone and somatostatin. Any genetic or acquired disorder that impairs GH secretion or action causes a pathological phenotype characterized by harmonic short stature with isolated GH deficiency (IGHD) or combined pituitary hormone deficiency (CPHD). In this article we report current knowledge about the genetic basis of IGHD and CPHD.

Ghrelin gene polymorphisms and ghrelin, insulin, IGF-I, leptin and anthropometric data in children and adolescents

BACKGROUND

Previous investigations on the ghrelin gene reported three common polymorphisms (Arg51Gln, Leu72Met, and Gln90Leu), but their role in overweight and obese individuals remains to be clarified.

OBJECTIVE

To ascertain whether these genetic variants could influence ghrelin secretion and play a part in predisposing to earlier onset of obesity or in modulating the overweight phenotype in childhood.

DESIGN AND METHODS

Mutational analysis of the entire ghrelin gene and total and acylated plasma determinations were performed in 81 obese or overweight children and adolescents (46 were obese and 35 overweight: Ob/Ow). We also recruited 168 normal-weight healthy controls (72 young adults and 96 children) for mutational or plasma ghrelin analysis.

RESULTS

Median total and acylated plasma ghrelin concentrations were significantly lower in Ob/Ow individuals than in controls (175 pg/ml compared with 345 pg/ml, P<0.0001, and 95 pg/ml compared with 114 pg/ml, P<0.0001, respectively). The ghrelin gene variants showed similar allele frequencies in the Ob/Ow individuals and in controls; in the former, they were not associated with any change in total and acylated circulating ghrelin concentrations or anthropometric data. The Leu72Met status was associated with a positive family history for obesity (75% for Leu72Met compared with 39% for Leu72Leu, P=0.03) and with a greater percentage of newborns born 'large for gestational age' (33% for Leu72Met compared with 5% for Leu72Leu, P=0.03), but in the control group it was related to a lower mean body mass index z-score (-0.03 for Leu72Met and -0.47 for Leu72Leu, P=0.04).

CONCLUSION

Our present findings do not support the hypothesis that the ghrelin gene polymorphisms have a relevant impact in the secretion of total and acylated ghrelin.

The effects of insulin on mesenteric blood flow in anaesthetized pigs

Infusion of insulin in anaesthetized pigs has been shown to cause an increase in renal blood flow and a decrease in coronary blood flow, which were the net result of a vasoconstriction involving sympathetic alpha-adrenoceptor-mediated mechanisms and of a local vasodilatation involving the endothelial release of nitric oxide. In the present study, the effect of insulin on superior mesenteric blood flow was examined in pentobarbitone-anaesthetized pigs at constant heart rate, aortic blood pressure, left ventricular contractility and blood levels of glucose and potassium. In 10 pigs, infusion of 0.004 IU kg(-1) min(-1) of insulin increased mesenteric flow. In five of these pigs, intravenous phentolamine enhanced the increase in mesenteric flow elicited by insulin, a response which was abolished by the subsequent injection of N(omega)-nitro-L-arginine methyl ester (L-NAME) into the mesenteric artery. In the remaining five pigs, infusion of insulin after intramesenteric injection of L-NAME caused a decrease in mesenteric flow. This response was abolished by the subsequent intravenous administration of phentolamine. The present study showed that infusion of insulin in anaesthetized pigs primarily caused a mesenteric vasodilatation, which was the net result of two opposite effects, namely a predominant vasodilatation mediated by the endothelial release of nitric oxide and a sympathetic vasoconstrictor mechanism mediated by alpha-adrenoceptors.

Circulating ghrelin levels in the newborn are positively associated with gestational age

OBJECTIVE

Ghrelin exerts potent GH-releasing activity and stimulates food intake. Circulating ghrelin levels are increased in anorexia and cachexia, reduced in obesity and restored by weight recovery. Newborns are characterized by GH hypersecretion associated with low IGF-I levels reflecting peripheral GH resistance.

STUDY DESIGN

The aim of our study was to measure cord ghrelin levels in 117 newborns appropriate for gestational age, born either at term or preterm.

RESULTS

Ghrelin levels in cord blood (median; 25th-75th centile: 327.6; 206.0-413.0 pg/ml) were higher (P < 0.0001) than those in maternal blood at delivery (133.0; 89.0-173.7 pg/ml), without gender differences. A positive correlation between ghrelin levels in mothers and newborns (r = 0.26, P < 0.01) was observed. Ghrelin levels in newborns born at term (399.0; 229.0-438.0 pg/ml) were remarkably higher (P < 0.0001) than those in born preterm (208.0; 144.5-278.9 pg/ml). A clear positive association was present between ghrelin levels and gestational age. No association between ghrelin and GH, IGF-I, insulin, glucose and leptin levels were found.

CONCLUSIONS

Cord ghrelin levels show clear gestational age-related dependency. The lack of any direct relationship between ghrelin and anthropometric or biochemical parameters in adequate for gestational age newborns does not support the hypothesis that ghrelin has major role in foetal GH secretion and growth.

Hyperparathyroidism

Hyperparathyroidism is a disease characterized by hypercalcemia with hypophosphoremia resulting from increased secretion of parathyroid hormone (PTH). The disease may be divided into 3 forms: a) primary, b) secondary, c) tertiary (secondary refractory form). Primary hyperparathyroidism is rare in children; hyperplasia is more frequent during the early years of life (neonates and infants) and is difficult to distinguish from adenoma in children. The disease may be asymptomatic; elevated calcemia levels (>12 <13.5 mg/dl) are accompanied by anorexia, asthenia and persistent stipsis; severely elevated concentrations (>13.5 mg/dl) are accompanied by nausea, vomiting, polyuria due to osmosis, with dehydration and progressive onset of lethargy, stupor and coma. Osteopenia or osteitis fibrosa cystica may be present due to augmented bone resorption. Height and weight increases are altered due to anorexia and dehydration. Differential diagnosis includes iatrogenic causes of hypercalcemia (excessive vitamin D intake, prolonged immobilization, etc.) and idiopathic familial hypercalcemia. Emergency treatment is required in cases of extremely elevated hypercalcemia (Ca >13.5-14 mg/dl), due to risk of injury to the heart, the central nervous system, the gastrointestinal tract and the kidneys. The 4 cardinal points of treatment are: hydration, calciuresis, inhibition of bone calcium resorption, treatment of the cause underlying hyperparathyroidism. Secondary hyperparathyroidism is found in cases where chronic hypocalcemia is present, particularly in chronic renal failure, untreated deficiency rickets, chronic intestinal malabsorption, hepatobiliary disease, types I and II vitamin D-dependent rickets, tubular acidosis or Fanconi's syndrome. The tertiary form is distinguished by the autonomous nature of the parathyroid glands which have become hypertrophic/hyperplastic due to uncontrollable, chronic severe renal failure. It can also be of iatrogenic origin due to excessive intake of inorganic phosphates in familial hypophosphatemic rickets or chronic vitamin D deficiency.

Leptin levels as function of age, gender, auxological and hormonal parameters in 202 healthy neonates at birth and during the first month of life

Leptin signals to the brain energy stores and balance while integrating neuroendocrine functions. Leptin levels in adults are higher in females than in males, while a gender-related difference in newborns is controversial. To clarify this point, in 202 healthy neonates we measured dynamic changes in leptin levels over the first month of life and looked for correlation between leptin levels and auxological and hormonal parameters. Cord leptin concentration in females was higher (p < 0.001) than in males. IGF-I, IGF-II, insulin, testosterone and 17beta-estradiol levels were similar in both sexes while insulin-like growth factor binding protein 3 (IGF-BP3) levels in females were slightly higher than in males. Leptin levels were positively associated to body weight, gestational age, IGF-BP3 levels, insulin levels and maternal body mass index (BMI) at time of delivery. In a subset of subjects (no. = 65), in comparison with cord levels, serum leptin levels were decreased on the 5th day of life (p < 0.0001) and then increased at 1 month (p < 0.0001). Positive association between leptin and weight was lost on the 5th day of life but present again at 1 month. In conclusion, our findings in a large population of neonates definitely show that leptin levels at birth are functions of gender, body weight and gestational age but not of length, cranial circumference, IGF-I and IGF-II levels. These findings, coupled with weight-independent prompt decrease after birth followed by weight-dependent increase at one month of life, suggest that leptin secretion in neonates as well as in adults mainly signals the nutritional state to the brain.

Standard light breakfast inhibits circulating ghrelin level to the same extent of oral glucose load in humans, despite different impact on glucose and insulin levels

Ghrelin levels are increased by fasting and energy restriction, decreased by food intake, glucose load and insulin but not by lipids and amino acids. Accordingly, ghrelin levels are elevated in anorexia and cachexia and reduced in obesity. Herein we compared the effects of a standardized light breakfast (SLB) on morning circulating ghrelin levels with those of oral glucose load (OGTT) in normal subjects. Specifically, 8 young adult volunteers [age (mean+/-SEM): 28.0+/-2.0 yr; body mass index (BMI): 22.4+/-0.6 kg/m2] underwent the following testing sessions: a) OGTT (100 g p.o. at 0 min, about 400 kcal); b) SLB (about 400 kcal, 45% carbohydrates, 13% proteins and 42% lipids at 0 min) on three different days; c) placebo (100 ml water p.o.). In all sessions, at baseline, blood samples were withdrawn twice at 5-min interval to characterize the inter- and intra-individual reproducibility of the variables assayed. After placebo and OGTT, blood samples were withdrawn every 15 min up to +120 min. After SLB, blood samples were taken at 60 min only. Ghrelin, insulin and glucose levels were assayed at each time point in all sessions. Similarly to insulin and glucose levels, at baseline, ghrelin showed remarkable intra-subject reproducibility both in the same sessions and among the different sessions. Placebo did not significantly modify ghrelin, insulin and glucose. OGTT increased (p<0.01) glucose (baseline vs peak: 80.0+/-3.6 vs 140.5+/-6.3 mg/dl) and insulin (20.2+/-6.2 vs 115.3+/-10.3 mU/l) levels. SLB increased (p<0.05) both insulin (16.3+/-1.8 vs 48.3+/-6.3 mU/l) and glucose (74.5+/-3.7 vs 82.9+/-3.1 mg/dl) levels. Notably both the insulin and glucose increases after OGTT were significantly higher (p<0.01) than that induced by SLB. After OGTT, ghrelin levels underwent a significant reduction (baseline vs nadir: 355.7+/-150.8 vs 243.3+/-98.8 pg/ml; p<0.05) reaching the nadir at time +60 min. Similarly, ghrelin levels 60 min after SLB (264.8+/-44.8 pg/ml) were significantly (p<0.01) lower than at baseline (341.4+/-54.9 pg/ml). No significant differences in the reduction of ghrelin levels after OGTT and SLB were observed. In conclusion, these findings show that light breakfast inhibits ghrelin secretion to the same extent of OGTT in adults despite lower variations in glucose and insulin levels.

Defective function of Fas in T cells from paediatric patients with autoimmune thyroid diseases

Triggering of the Fas receptor induces T cell apoptosis and is involved in shutting-off the immune response. Inherited defects impairing Fas function cause the autoimmune lymphoproliferative syndrome, and may play a role in other autoimmune diseases. The aim of this work was to analyse the Fas function in paediatric patients with thyroid autoimmunities. We found that T cells from 24/28 patients with Graves' disease (GD) and 12/35 patients with Hashimoto's thyroiditis (HT) displayed defective Fas function. In HT, the defect was more frequent in patients requiring replacement therapy (11/20) than in those not requiring (1/15); moreover, in untreated HT the highest defect was displayed by patients with the highest levels of autoantibodies. Fas was always expressed at normal levels and no Fas mutations were detected. Analysis of the healthy parents of seven Fas-resistant patients showed that several of them were Fas-resistant, which suggests a genetic component. Fusion of Fas-resistant T cells with the Fas-sensitive HUT78 T cell line generated Fas-resistant hybrid cells, which suggests the presence of molecules exerting a dominant negative effect on Fas function. Analysis of Fas-induced activation of caspase-8 and -9 showed decreased activity of both caspases in HT, whereas activity of caspase-9 was increased and that of caspase-8 was decreased in GD. These data suggest that heterogeneous inherited defects impairing Fas function favour the development of thyroid autoimmunities.

Central and peripheral activities of ghrelin, a ligand of the growth hormone secretagogue receptor

Ghrelin, a 28 amino-acid acylated peptide predominantly produced by the stomach, displays strong GH-releasing activity mediated by the hypothalamus-pituitary GH secretagogues (GHS) receptors which had been shown specific for a family of synthetic, orally active GHS. GHS also act on central and peripheral receptors and show other actions including an orexigenic effect, influence on gastro-entero-pancreatic functions, cardiovascular and anti-proliferative effects. Ghrelin manages the neuroendocrine and metabolic response to starvation. Taking into account its orexigenic effect, GHS analogues acting as agonists or antagonists on appetite could represent new drug intervention in eating disorders.

Two new PROP1 gene mutations responsible for compound pituitary hormone deficiency

Mutations in the Prophet of Pit-1 (Prop-1), a paired-like homeodomain transcription factor involved in the early embryonic pituitary development, have been reported as a cause of combined hormone deficiency (CPHD) involving growth hormone (GH), prolactin (PRL), thyroid-stimulating hormone (TSH), gonadotrophins and in some cases adrenocorticotrophic hormone (ACTH). We report two pre-pubertal siblings with short stature and deficiency of GH and TSH at presentation. Molecular analysis of the PROP1 gene revealed compound heterozygotes for two novel missense mutations of the PROP1 gene affecting the same amino acid (Arg71Cys and Arg71His) in the first alpha helix of the Prop-1 homeodomain.

Circulating ghrelin levels in newborns are not associated to gender, body weight and hormonal parameters but depend on the type of delivery

Ghrelin, a new gastric-derived hormone, probably plays a major role in managing energy balance and the neuroendocrine response to starvation. Information about the age-related variation in ghrelin secretion is scanty. We measured circulating ghrelin levels in 93 full term newborns adequate for gestational age, in 39 normal children and in 19 lean healthy adults. Our findings demonstrate that ghrelin levels are independent of age and gender from birth to adulthood. Interestingly, ghrelin secretion at birth is not associated to body weight and hormonal parameters such as GH, insulin and leptin levels. On the other hand, ghrelin levels seem dependent on the type of delivery, being lower in newborns after caesarean section with respect to those after normal delivery.

Does Graves' disease during puberty influence adult bone mineral density?

AIM

To evaluate the bone mineral density at lumbar spine and at femoral neck in a group of young adults in whom Graves' disease developed during childhood and adolescence.

PATIENTS AND METHODS

We examined 28 patients (5 male, 23 female, age 20.9 +/- 3.3 years) who were 11.8 +/- 2.9 years old at the onset of Graves' disease. They were treated either with methimazole (14 patients) or with methimazole plus l-thyroxine (14 patients). At the time of the investigation, 13 patients were considered cured following antithyroid treatment, 2 were still on antithyroid drugs, 3 were on replacement therapy with l-thyroxine because of hypothyroidism, and 10, treated either surgically or with (131)I, were on replacement therapy. The bone mineral density was measured at the lumbar spine (L2-L4) and at the femoral neck, using dual-energy X-ray absorptiometry.

RESULTS

The spinal bone mineral density SD score was -0.28 +/- 1.02, the femoral neck bone mineral density SD score was 0.36 +/- 1.02, and both were not different from zero (NS). We did not find any correlation between the bone mineral density of the femoral neck and that of the lumbar spine and the clinical parameters.

CONCLUSION

Graves' disease, beginning in childhood and adolescence, when appropriately treated, does not affect attainment of peak bone mass.

[Secular trend of puberty]

The aim of our study was to evaluate the age of the onset of pubertal characteristics in a population of Northern Italy and to compare our data with the pubertal staging scale defined by Tanner in 1976. These observations may help us to verify if even in Italy there is a positive secular change in sexual maturation, as has been observed in many European countries. We studied 3510 children (1868 males and 1642 females) aged 6-15 years, born between 1983 and 1996. In every subject sexual maturity was evaluated according to Tanner stages. We calculated the percentile distribution for ages of attainment of B2 and PH2 stages for females and G2, PH2 and testicular volume = or >4 ml (VT4) for males. In females the percentile values for B2 were: 3rd=8.1, 50th=10.5, and 97th=12.6 years. In males the percentile values for G2 and VT4 were: 3rd=8.8 and 9.1 years respectively, 50th=11 years, and 97th=13.4 and 13.3 years respectively. 3rd, 50th, and 97th centiles for pubic hair stage 2 were 8.1, 10.6 and 12.6 years for females and 8.8, 11.2 and 13.4 years for males. For all stages an earlier pubertal development was seen in comparison with Tanner data. One hundred-twenty-five girls had already reached menarche. Median (interquartile range) age at menarche was 11.9 (11.4-12.4) years showing a decrease compared with Tanner values. Our data clearly demonstrate a positive secular trend in pubertal development and point out the need of having updated references values of the timing of sexual maturation for the whole Italian population.

Effects of insulin on coronary blood flow in anesthetized pigs

Insulin can influence the vasculature by a sympathetically mediated vasoconstriction and a vasodilatation; the latter effect predominates in the renal circulation of anesthetized pigs. We determined the effect of intravenous infusion of insulin on coronary blood flow in pentobarbitone-anesthetized pigs at constant heart rate, arterial pressure and blood levels of glucose and potassium. In 6 pigs, infusion of 0.004 IU kg(-1) min(-1) of insulin decreased coronary flow despite increasing left ventricular dP dT(max)(-1); when the latter was abolished by propranolol, the coronary flow response was augmented. The mechanisms of this response were examined in 22 pigs given propranolol. Phentolamine changed coronary flow response to an increase (6 pigs) and this was abolished by intracoronary injection of N(omega)-nitro-L-arginine methyl ester (L-NAME; 5 pigs). L-NAME augmented coronary flow response (6 pigs) and this was abolished by phentolamine (5 pigs). In 18 pigs given propranolol, three incremental doses of insulin caused graded coronary flow decreases whether L-NAME was given (6 pigs) or not (6 pigs) beforehand, and caused graded coronary flow increases after phentolamine (6 pigs). Thus insulin caused a coronary vasoconstriction mediated by sympathetic alpha-adrenergic effects and a vasodilatation related to the release of nitric oxide. The net effect was a coronary vasoconstriction.

Foetal and neonatal thyroid disorders

Thyroid hormones have been shown to be absolutely necessary for early brain development. During pregnancy, both maternal and foetal thyroid hormones contribute to foetal brain development and maternal supply explains why most of the athyreotic newborns usually do not show any signs of hypothyroidism at birth. Foetal and/or neonatal hypothyroidism is a rare disorder. Its incidence, as indicated by neonatal screening, is about 1:4000. Abnormal thyroid development (i.e. agenesia, ectopic gland, hypoplasia) or inborn errors in thyroid hormone biosynthesis are the most common causes of permanent congenital hypothyroidism. Recent studies reported that mutations involving Thyroid Transcriptor Factors (TTF) such as TTF-1, TTF-2, PAX-8 play an important role in altered foetal thyroid development. Deficiency of transcriptor factor (Pit-1, Prop-1, LHX-3) both in mother and in the foetus represents another rare cause of foetal hypothyroidism. At birth clinical picture may be not always so obvious and typical signs appear only after several weeks but a delayed diagnosis could have severe consequences consisting of delayed physical and mental development. Even if substitutive therapy is promptly started some learning difficulties might still arise suggesting that intrauterine adequate levels of thyroid hormones are absolutely necessary for a normal neurological development. Placental transfer of maternal antithyroid antibodies inhibiting fetal thyroid function can cause transient hypothyroidism at birth. If the mother with thyroid autoimmune disease is also hypothyroid during pregnancy and she doesn't receive substitutive therapy, a worse neurological outcome may be expected for her foetus. Foetal and/or neonatal hyperthyroidism is a rare condition and its incidence has been estimated around 1:4000-40000, according to various authors. The most common causes are maternal thyroid autoimmune disorders, such as Graves' disease and Hashimoto's thyroiditis. Rarer non autoimmune causes recently identified are represented by TSH receptor mutations leading to constitutively activated TSH receptor. Infants born to mothers with Graves' history may develop neonatal thyrotoxicosis. Foetal/neonatal disease is due to transplacental thyrotrophin receptor stimulating antibodies (TRAb) passage. It's extremely important recognizing and treating Graves' disease in mothers as soon as possible, because a thyrotoxic state may have adverse effects on the outcome of pregnancy and both on the foetus and newborn. Thyrotoxic foetuses may develop goitre, tachycardia, hydrops associated with heart failure, growth retardation, craniosynostosis, increased foetal motility and accelerated bone maturation. Neonatal Graves' disease tends to resolve spontaneously within 3-12 weeks as maternal thyroid stimulating immunoglobulins are cleared from the circulation but subsequent development may be impaired by perceptual motor difficulties. Hashimoto's thyroiditis is a very common autoimmune thyroid disease. In presence of maternal Hashimoto's thyroiditis, there are usually no consequences on foetal thyroid, even if antiTPO and antiTg antibodies can be found in the newborn due to transplacental passage. However there are some literature reports describing foetal and neonatal hyperthyroidism in the affected mothers' offspring.

Short children with familial short stature show enhancement of somatotroph secretion but normal IGF-I levels

The aim of the present study was to evaluate the GH status in children with familial, idiopathic short stature (FSS). To this goal we evaluated the GH response to GHRH (1 microg/kg iv) + arginine (ARG) (0.5 g/kg iv) test which is one of the most potent and reproducible provocative tests of somatotroph secretion, in 67 children with FSS [50 boys and 17 girls, age 10.8+/-0.4 yr, pubertal stages I-III, height between -3.6 and -1.6 standard deviation score (SDS), target height <10 degrees centile, normality of both spontaneous and stimulated GH secretion as well as of IGF-I levels]. The results in FSS were compared with those in groups of children of normal height (NHC) (42 NHC, 35 boys and 7 girls, age 12.0+/-0.5 yr, pubertal stages I-III, height between -1.3 and 1.4 SDS, height velocity standard deviation score (HVSDS)>25 degrees centile, GH peak >20 microg/l after GHRH+ARG test, mean GH concentration [mGHc]>3 microg/l) and children with organic GH deficiency (GHD) (38 GHD, 29 boys and 9 girls, age 11.2+/-3.7 yr, pubertal stages I-III, height between -5.7 and -1.3 SDS, GH peak <20 microg/l after GHRH +ARG test, mGHc <3 mg/l). Basal IGF-I levels and mGHc were also evaluated in each group over 8 nocturnal hours. IGF-I levels in FSS (209.2+/-15.6 microg/l) were similar to those in NHC (237.2+/-17.2 microg/l) and both were higher (p<0.0001) than those in GHD (72.0+/-4.0 microg/l). The GH response to GHRH +ARG test in FSS (peak: 66.4+/-5.6 microg/l) was very marked and higher (p<0.01) than that in NHC (53.3+/-4.5 microg/l) which, in turn, was higher (p<0.01) than in GHD (8.2+/-0.8 microg/l). Similarly, the mGHc in FSS was higher than in NHC (6.7+/-0.5 microg/l vs 5.1+/-0.7 microg/l, p<0.05) which, in turn, was higher than in GHD (1.5+/-0.2 microg/l, p<0.0001). In conclusion, our present study demonstrates that short children with FSS show enhancement of both basal and stimulated GH secretion but normal IGF-I levels. These findings suggest that increased somatotroph function would be devoted to maintain normal IGF-I levels thus reflecting a slight impairment of peripheral GH sensitivity in FSS.

Circulating ghrelin levels as function of gender, pubertal status and adiposity in childhood

Ghrelin, a natural GH secretagogue, exerts remarkable endocrine and non-endocrine activities such as orexigenic effect and modulation of the endocrine and metabolic response to variations in energy balance. Ghrelin levels have been reported to be negatively associated to insulin secretion, enhanced in anorexia and reduced in obesity. Ghrelin levels in childhood have never been evaluated. We measured morning ghrelin levels after overnight fasting in 29 healthy lean children (NC) and in 36 obese children (OBC). The results were compared with those recorded twice in 3 different sessions in healthy lean adults (NA). In NA ghrelin levels showed good within-subject reproducibility without gender-related differences. Ghrelin levels in NC [(median; 25 degrees -75 degrees centile): 426.0; 183.0-618.0 pg/ml] were similar to those in NA (380.5; 257.7-551.7 pg/ml). Ghrelin levels in OBC (229.5; 162.5-339.5 pg/ml) were lower (p<0.03) than in NC (426.0; 183.0-618.0 pg/ml). Both in NC and in OBC, ghrelin levels were independent of gender and pubertal status. In all children, ghrelin levels were negatively associated (p<0.05) to weight excess (r=-0.24), insulin (r=-0.28) and IGF-I (r=-0.4) levels. In conclusion, these findings demonstrate that morning ghrelin levels after overnight fasting show good within-subject reproducibility, and are similar in both sexes and do not vary from childhood to adulthood. In childhood, circulating ghrelin levels are reduced in obese subjects being negatively correlated to overweight and insulin secretion.