Effects of physical training on serum and pituitary growth hormone contents in diabetic rats

The present study investigated the effects of moderate physical training on some of the parameters in the GH-IGF axis in experimental diabetic rats. Male Wistar rats were allocated into the following groups: sedentary control, trained control, sedentary diabetic, trained diabetic. Diabetes was induced by alloxan (32 mg/kg, b.w. iv). The physical training protocol consisted of 1 h swimming session/day, 5 days/week for 8 weeks supporting a load corresponding to 90% of maximal lactate steady state. After the experimental period, blood was collected to measure serum glucose, insulin, triglycerides, albumin, insulin-like growth factors-I (IGF-I), and growth hormone (GH). Pituitary gland was removed for GH quantification. Diabetes increased blood glucose and triglycerides and decreased insulin, IGF-I, serum and pituitary GH. Physical training decreased glucose and triglycerides, and also counteracted the reduction of serum IGF-I in diabetic rats. In conclusion, physical training recovered serum IGF-I showing no alteration of serum or pituitary GH levels.

Growth hormone mRNA expression in the pituitary of Bos indicus and Bos taurus x Bos indicus crossbred young bulls treated with recombinant bovine somatotropin

The effects of breed and of recombinant bovine somatotropin (rbST) treatment on growth hormone gene expression were studied in young bulls. The experiment was completely randomized in a [2 × 2]-factorial arrangement, using two levels of rbst (0 or 250 mg/animal/14 days), and two breed groups (Nelore and Simmental x Nelore crossbred). A CDNA encoding Bos indicus growth hormone was cloned and sequenced for use as a probe in Northern and dot blot analyses. Compared to the Bos taurus structural gene, the Bos indicus CDNA was found to begin 21 bases downstream from the transcription initiation site and had only two discrepancies (C to T at position 144-His and T to C at position 354-Phe), without changes in the polypeptide sequence. However, two amino acid substitutions were found for Bubalus spp., which belong to the same tribe. The rbst treatment did not change any of the characteristics evaluated (body and pituitary gland weights, growth hormone MRNA expression level). Crossbred animals had significantly higher body weight and heavier pituitaries than Nelore cattle. Pituitary weight was proportional to body weight in both breed groups. Growth hormone MRNA expression in the pituitary was similar (P>0.075) for both breed and hormonal treatment groups, but was 31.9% higher in the pure Nelore group, suggesting that growth hormone gene transcription regulation differs among these breeds.

Diagnosis of 5α-reductase type 2 deficiency: Contribution of anti-Müllerian hormone evaluation

Aim: To evaluate anti-Müllerian hormone (AMH) levels in patients with clinical and molecular diagnosis of 5α-reductase 2 deficiency. Patients and methods: Data from 14 patients whose age ranged from 21 days to 29 years were analyzed according to age and pubertal stage. Sexual ambiguity was rated as Prader III in 11 patients. LH, FSH, testosterone (T), dihydrotestosterone (DHT) and AMH serum levels were measured in all but two patients, who had been previously submitted to gonadectomy; T and DHT were also measured in 20 age-matched controls. Results: Gonadotropin levels were normal in all but one patient who retained gonads (six of whom had reached puberty) and T/DHT ratio was elevated in all patients when compared to controls. All prepubertal patients had AMH levels < -1 SD for age, while most pubertal patients had AMH levels compatible with pubertal stage. Conclusions: Prepubertal patients with 5α-reductase 2 deficiency have AMH values in the lower part of the normal range. These data indicate that T does not need to be converted to DHT to inhibit AMH secretion by Sertoli cells. © Freund Publishing House Ltd., London.

Cost-effectiveness comparison between pituitary down-regulation with a gonadotropin-releasing hormone agonist short regimen on alternate days and an antagonist protocol for assisted fertilization treatments

Objective: To compare cost-effectiveness between pituitary down-regulation with a GnRH agonist (GnRHa) short regimen on alternate days and GnRH antagonist (GnRHant) multidose protocol on in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) outcome. Design: Prospective, randomized. Setting: A private center. Patient(s): Patients were randomized into GnRHa (n = 48) and GnRHant (n = 48) groups. Intervention(s): GnRHa stimulation protocol: administration of triptorelin on alternate days starting on the first day of the cycle, recombinant FSH (rFSH), and recombinant hCG (rhCG) microdose. GnRHant protocol: administration of a daily dose of rFSH, cetrorelix, and rhCG microdose. Main Outcome Measure(s): ICSI outcomes and treatment costs. Result(s): A significantly lower number of patients underwent embryo transfer in the GnRHa group. Clinical pregnancy rate was significantly lower and miscarriage rate was significantly higher in the GnRHa group. It was observed a significant lower cost per cycle in the GnRHa group compared with the GnRHant group ($5,327.80 ± 387.30 vs. $5,900.40 ± 472.50). However, mean cost per pregnancy in the GnRHa was higher than in the GnRHant group ($19,671.80 ± 1,430.00 vs. $11,328.70 ± 907.20). Conclusion(s): Although the short controlled ovarian stimulation protocol with GnRHa on alternate days, rFSH, and rhCG microdose may lower the cost of an individual IVF cycle, it requires more cycles to achieve pregnancy. Clinical Trial Registration Number: NCT01468441. © 2013 by American Society for Reproductive Medicine.

Growth hormone response to growth hormone-releasing peptide-2 in growth hormone-deficient Little mice

OBJECTIVE: To investigate a possible direct, growth hormone-releasing, hormone-independent action of a growth hormone secretagogue, GHRP-2, in pituitary somatotroph cells in the presence of inactive growth hormone-releasing hormone receptors. MATERIALS AND METHODS: The responses of serum growth hormone to acutely injected growth hormone-releasing P-2 in lit/litmice, which represent a model of GH deficiency arising frommutated growth hormone-releasing hormone-receptors, were compared to those observed in the heterozygous (lit/+) littermates and wild-type (+/+) C57BL/6J mice. RESULTS: After the administration of 10 mcg of growth hormone-releasing P-2 to lit/lit mice, a growth hormone release of 9.3 +/- 1.5 ng/ml was observed compared with 1.04 +/- 1.15 ng/ml in controls (p<0.001). In comparison, an intermediate growth hormone release of 34.5 +/- 9.7 ng/ml and a higher growth hormone release of 163 +/- 46 ng/ml were induced in the lit/+ mice and wild-type mice, respectively. Thus, GHRP-2 stimulated growth hormone in the lit/lit mice, and the release of growth hormone in vivo may be only partially dependent on growth hormone-releasing hormone. Additionally, the plasma leptin and ghrelin levels were evaluated in the lit/lit mice under basal and stimulated conditions. CONCLUSIONS: Here, we have demonstrated that lit/lit mice, which harbor a germline mutation in the Growth hormone-releasing hormone gene, maintain a limited but statistically significant growth hormone elevation after exogenous stimulation with GHRP-2. The present data probably reflect a direct, growth hormone-independent effect on Growth hormone S (ghrelin) stimulation in the remaining pituitary somatotrophs of little mice that is mediated by growth hormone S-R 1a.

GH-Releasing Hormone Receptor Gene: A Novel Splice-Disrupting Mutation and Study of Founder Effects

Background: Mutations in GH-releasing hormone receptor gene (GHRHR) are emerging as the most common cause of autosomal recessive isolated GH deficiency (IGHD). Objective: To search for GHRHR mutations in patients with familial or sporadic IGHD and to investigate founder effects in recurring mutations. Methods: The coding region of GHRHR was entirely amplified and sequenced from DNA of 18 patients with IGHD (16 unrelated) with topic posterior pituitary lobe on MRI. Haplotypes containing promoter SNPs and microsatellites flanking GHRHR were analyzed in patients with c.57+1G>A (IVS1+1G>A) mutation of our previously published kindred and also a Brazilian patient and 2 previously reported Japanese sisters with c. 1146G>A (p.E382E) mutation. Results: A novel homozygous intronic GHRHR c.752-1G>A (IVS7-1G>A) mutation, predicting loss of the constitutive splice acceptor site, was identified in two siblings with IGHD. A compound heterozygous c.[57+1G>A];[1146G>A] and a heterozygous c.527C>T (p.A176V) were found in two sporadic cases. Haplotype analysis provided evidence for a founder effect for the c.57+1G>A mutation and independent recurrence for the c.1146G>A mutation. Conclusion: We report a novel splice-disrupting mutation in GHRHR in 2 siblings and provide evidence that all c.57+1G>A (IVS1+1G>A) mutant chromosomes have the same haplotype ancestor, indicating the occurrence of a founder effect in Brazilian patients with IGHD. Copyright (C) 2012 S. Karger AG, Basel

Growth hormone response to growth hormone-releasing peptide-2 in growth hormone-deficient Little mice

OBJECTIVE: To investigate a possible direct, growth hormone-releasing, hormone-independent action of a growth hormone secretagogue, GHRP-2, in pituitary somatotroph cells in the presence of inactive growth hormonereleasing hormone receptors. MATERIALS AND METHODS: The responses of serum growth hormone to acutely injected growth hormone-releasing P-2 in lit/litmice, which represent a model of GH deficiency arising frommutated growth hormone-releasing hormonereceptors, were compared to those observed in the heterozygous (lit/+) littermates and wild-type (+/+) C57BL/6J mice. RESULTS: After the administration of 10 mcg of growth hormone-releasing P-2 to lit/lit mice, a growth hormone release of 9.3±1.5 ng/ml was observed compared with 1.04±1.15 ng/ml in controls (p<0.001). In comparison, an intermediate growth hormone release of 34.5±9.7 ng/ml and a higher growth hormone release of 163±46 ng/ml were induced in the lit/+ mice and wild-type mice, respectively. Thus, GHRP-2 stimulated growth hormone in the lit/lit mice, and the release of growth hormone in vivo may be only partially dependent on growth hormone-releasing hormone. Additionally, the plasma leptin and ghrelin levels were evaluated in the lit/lit mice under basal and stimulated conditions. CONCLUSIONS: Here, we have demonstrated that lit/lit mice, which harbor a germline mutation in the Growth hormone-releasing hormone gene, maintain a limited but statistically significant growth hormone elevation after exogenous stimulation with GHRP-2. The present data probably reflect a direct, growth hormone-independent effect on Growth hormone S (ghrelin) stimulation in the remaining pituitary somatotrophs of little mice that is mediated by growth hormone S-R 1a.

Growth hormone (GH) deficiency type II: a novel GH-1 gene mutation (GH-R178H) affecting secretion and action

Context and Objective: Main features of the autosomal dominant form of GH deficiency (IGHD II) include markedly reduced secretion of GH combined with low concentrations of IGF-I leading to short stature. Design, Setting, and Patients: A female patient presented with short stature (height -6.0 sd score) and a delayed bone age of 2 yr at the chronological age of 5 yr. Later, at the age of 9 yr, GHD was confirmed by standard GH provocation test, which revealed subnormal concentrations of GH and a very low IGF-I. Genetic analysis of the GH-1 gene revealed the presence of a heterozygous R178H mutation. Interventions and Results: AtT-20 cells coexpressing both wt-GH and GH-R178H showed a reduced GH secretion after forskolin stimulation compared with the cells expressing only wt-GH, supporting the diagnosis of IGHD II. Because reduced GH concentrations found in the circulation of our untreated patient could not totally explain her severe short stature, functional characterization of the GH-R178H performed by studies of GH receptor binding and activation of the Janus kinase-2/signal transducer and activator of transcription-5 pathway revealed a reduced binding affinity of GH-R178H for GH receptor and signaling compared with the wt-GH. Conclusion: This is the first report of a patient suffering from short stature caused by a GH-1 gene alteration affecting not only GH secretion (IGHD II) but also GH binding and signaling, highlighting the necessity of functional analysis of any GH variant, even in the alleged situation of IGHD II.

Isolated GH deficiency type II: knockdown of the harmful Delta3GH recovers wt-GH secretion in rat tumor pituitary cells

Isolated GH deficiency type II (IGHD II) is the autosomal dominant form of GHD. In the majority of the cases, this disorder is due to specific GH-1 gene mutations that lead to mRNA missplicing and subsequent loss of exon 3 sequences. When misspliced RNA is translated, it produces a toxic 17.5-kDa GH (Delta3GH) isoform that reduces the accumulation and secretion of wild-type-GH. At present, patients suffering from this type of disease are treated with daily injections of recombinant human GH in order to maintain normal growth. However, this type of replacement therapy does not prevent toxic effects of the Delta3GH mutant on the pituitary gland, which can eventually lead to other hormonal deficiencies. We developed a strategy involving Delta3GH isoform knockdown mediated by expression of a microRNA-30-adapted short hairpin RNA (shRNA) specifically targeting the Delta3GH mRNA of human (shRNAmir-Delta3). Rat pituitary tumor GC cells expressing Delta3GH upon doxycycline induction were transduced with shRNAmir-Delta3 lentiviral vectors, which significantly reduced Delta3GH protein levels and improved human wild-type-GH secretion in comparison with a shRNAmir targeting a scrambled sequence. No toxicity due to shRNAmir expression could be observed in cell proliferation assays. Confocal microscopy strongly suggested that shRNAmir-Delta3 enabled the recovery of GH granule storage and secretory capacity. These viral vectors have shown their ability to stably integrate, express shRNAmir, and rescue IGHD II phenotype in rat pituitary tumor GC cells, a methodology that opens new perspectives for the development of gene therapy to treat IGHD patients.

Influence of growth hormone (GH) receptor deletion of exon 3 and full-length isoforms on GH response and final height in patients with severe GH deficiency

CONTEXT: A polymorphism of the GH receptor (GHR) gene resulting in genomic deletion of exon 3 (GHR-d3) has been associated with responsiveness to GH therapy. However, the data reported so far do vary according to the underlying condition, replacement dose, and duration of the treatment. OBJECTIVE, DESIGN: The aim of this study was to analyze the impact of the GHR genotypes in terms of the initial height velocity (HV) resulting from treatment and the impact upon adult height in patients suffering from severe isolated GH deficiency. CONTROLS, PATIENTS, SETTING: A total of 181 subjects (peak stimulated GHdeficiency, although the GHR genotype might play a role in GH responsiveness, at least at the beginning of treatment, there is no effect on final height.

Dyslipidaemia in Adult Growth Hormone (GH) Deficiency and the Effect of GH Replacement Therapy: A Review

Adult growth hormone (GH) deficiency is associated with a lipid profile known to be related to atherosclerosis. GH replacement therapy improves the lipid profile with the exception of lipoprotein (a) concentrations, which tend to increase after GH therapy. Plasma lipid concentrations depend on its plasma carriers, the lipoproteins. Possible mechanisms involved in the dyslipidaemia of GH-deficient patients and the effects of GH replacement therapy are discussed with a special focus on hepatic lipoprotein metabolism.