Growth Hormone Release Research Articles

Aerobic Exercise Increases Release of Growth Hormone in the Blood Circulation in Obese Women

Physical exercise is one of the modulators in increasing the release of growth hormone (GH) levels in blood circulation, but the effective exercise model for obese subjects is still being debated. Therefore, this study aims to prove the effect of aerobic exercise on increasing the release of GH levels in the blood circulation in obese women. A total of 20 obese adult women, aged 21.00 ± 1.08 years were selected to be subjects in the study and were given one aerobic exercise intervention by running on a treadmill at moderate-intensity (60-70% HRmax) for 40 minutes. The ELISA method was used to measure the release of GH levels in all samples (pre- and post-exercise). Statistical analysis in this study used an independent sample t-test with a significant level of 5%. The results showed that the release of GH levels in the blood circulation was found to be higher in post-exercise compared to pre-exercise after one session of aerobic exercise (484.92±128.29 vs 892.63±273.54 pg/mL; p=0.001) and has a large effect size with a Cohen's d value of 1.909. GH levels in the post-exercise blood circulation in the aerobic exercise group (Exr) were also found to be higher than the GH levels in the control group (Ctr) (892.63±273.54 vs 542.97±140.01 pg/mL; p=0.003) and has a large effect size with a Cohen's d value of 1.609. This study proves that one session of aerobic exercise with moderate intensity increases the release of circulating GH levels in obese women. Therefore, aerobic exercise with moderate intensity can be used as an alternative therapy option to increase the release of circulating GH levels in individuals with obesity. Keywords: aerobic exercise, growth hormone, metabolism, obesity.

Complementary role of peripheral and central autonomic nervous system on insulin-like growth factor-1 activation to prevent fatty liver disease.

Insulin-like growth factor-1 (IGF-1) is involved in the pathology of non-alcoholic fatty liver disease (NAFLD) and ameliorates fatty infiltration in the liver. It is activated by growth hormone (GH); however, the role of GH-IGF-1 axis in NAFLD developmental phase has not been well identified. Therefore, in this study, we focused on the effect of IGF-1 in NAFLD pathology and GH excretion activation from the pituitary gland by peripheral autonomic neural pathways relaying liver-brain-gut pathway and by central neuropeptides. GH and IGF-1 levels were assessed in wild-type and melanocortin-4 receptor knockout mice upon the development of diet-induced NAFLD. The contribution of the peripheral autonomic nervous system connecting the liver-brain-gut axis was assessed by its blockade using capsaicin and that of the central nervous system was assessed by the expression of hypothalamic brain-derived neurotrophic factor (BDNF) and corticotropin-releasing factor (CRH), which activates GH release from the pituitary gland. In the NAFLD mouse models, the levels of GH and IGF-1 increased (p < .05). Further, hepatic fatty infiltration was suppressed even under peripheral autonomic nervous system blockade (p < .001), which inhibited gastric ghrelin expression. In mice with peripheral autonomic nervous blockade, hypothalamic BDNF and CRH were inhibited (p < .05), resulting in GH and IGF-1 excretion, whereas other neuropeptides of somatostatin and cortistatin showed no changes. These complementary effects were canceled in melanocortin-4 receptor knockout mice, which diminished BDNF and CRH release control. Our study demonstrates that the release of IGF-1 by the nervous system is a key factor in maintaining the pathological homeostasis of NAFLD, suggesting its therapeutic potential.

Cationic exchange SPE combined with triple quadrupole UHPLC-MS/MS for detection of GHRHs in urine samples

The use of growth hormone-releasing hormones (GHRHs) is prohibited in sports according to the regulations of the World Anti-Doping Agency (WADA). Considering the complexity of urine samples and the low concentrations at which these analytes should be detected, analyzing GHRHs is a challenging task. In most of the studies, GHRHs are analyzed using UHPLC-HRMS with an orbitrap. The present developed and validated method for some GHRHs (tesamorelin, CJC-1295, sermorelin (GRF 1–29), sermorelin (3–29)-NH2, somatorelin) is based on the triple quadrupole UHPLC/MS-MS method with solid phase extraction (SPE) with weak cation exchange and is able to detect concentrations as low as 0.2 ng/mL (LOD), a limit of quantification (LOQ) at 0.6 ng/mL, and linearity across the range of 0.1 ng/mL to 1.2 ng/mL. The present method developed by our doping control laboratory was validated according to WADA technical documents for selectivity, limit of detection (LOD), carryover, reliability of detection, stability and recovery. The results show that the method has adequate recoveries and sensitivity, hence, it can be employed for routine screening in anti-doping laboratories.

THU373 Refractory Hypoglycemia In A Patient With Metastatic Cholangiocarcinoma: Abstract

Abstract Disclosure: M.G. Fernandez: None. D.J. Selen: None. Background: Nonislet cell tumor hypoglycemia is an uncommon but severe complication of cancer. It results from tumoral overproduction of insulin-like growth factor 2 (IGF-2), which inhibits hepatic glycogenolysis and the release of glucagon and growth hormone (GH). These three mechanisms can result in severe and refractory hypoglycemia. Clinical Case: We present a case of a 57-year-old female newly diagnosed with metastatic cholangiocarcinoma who was admitted to the hospital after an episode of syncope at home in the setting of hypoglycemia with a serum blood glucose of 17 mg/dL (N &amp;gt;60 mg/dL). During the hospital admission, evaluation of hypoglycemia included a normal TSH of 1.170 (reference range [RR] 0.3-5.5 mIU/ml), fasting morning cortisol of 23.3 (RR &amp;gt;14-15 μg/dL), and a negative sulfonylurea screen. In addition, the patient had an undetectable level of Insulin &amp;lt;3.0 (RR 3-25 mU/L), Beta-hydroxybutyrate &amp;lt;0.10 (RR 0.02-0.27 mMol/L), C-peptide &amp;lt;0.1 (RR 0.5-3.3 ng/ml), and Pro-insulin &amp;lt;1.6 (RR 3-20 pmol/L). CT of the abdomen revealed disease progression with innumerable bilateral enhanced hypoattenuating masses in the liver. Management for refractory hypoglycemia required nutrition optimization, nausea control, close glucose monitoring, IV dextrose infusion, and intermittent intravenous glucagon for episodes of severe hypoglycemia (&amp;lt;40 mg/dL). During the hospitalization, the patient received the first cycle of chemotherapy with gemcitabine, cisplatin, and dexamethasone. On day 10 of admission, the IGF-2 resulted at 120 ng/ml (RR 180-580ng/ml) and IGF-1&amp;lt;10 (RR 50-317 ng/ml) with an IGF-2/IGF-1 ratio greater than 100 (cut off&amp;gt;10), diagnostic of a large nonislet cell tumor as the most likely cause of her severe hypoglycemia. Artificial nutrition did not align with this patient’s goals of care, so she was discharged from the hospital with a FreeStyle Libre 2 for continuous glucose monitoring. However, two weeks later, she returned to the emergency department with hypoglycemia (&amp;lt;40 mg/dL), ultimately choosing to pursue hospice. Conclusion: Patients with large liver tumor burden can experience hypoglycemia due to low glycogen content in the liver. In addition, these patients can have decreased oral intake and weight loss, which confounds the clinical scenario and can delay diagnostic workup. Patients with refractory hypoglycemia and nonislet cell tumors require further evaluation for IGF-2 production, and alternative temporary nutritional options should be discussed with the patient immediately. Therapeutic options depend on the ability to treat underlying cancer. Palliative chemotherapy, surgery, or radiation can be considered to control the tumor and improve hypoglycemia for quality of life when the cancer is otherwise untreatable. Presentation: Thursday, June 15, 2023

THU043 Single-cell Transcriptomics Show Sex-specific Responses To A High Fat Diet, Under Thermoneutral Conditions, Pointing To Reduced Pituitary Plasticity

Abstract Disclosure: T.K. Miles: None. A.N. Lagasse: None. A.K. Odle: None. S.S. Lira: None. M.M. Syed: None. N. Akhter: None. M.C. MacNicol: None. A.M. MacNicol: None. G.V. Childs: None. Hyperinsulinemia caused by a high fat diet (HFD) directly suppressed pituitary growth hormone (Gh) and growth hormone releasing hormone receptor (Ghrhr) mRNAs (Luque and Kineman, 2006). To study the broader impact of a HFD, we exposed 3 groups of FVB.129P mice to 60% HFD for 10 or 15 wks at thermoneutrality (TN) (30 C), or 15 wks at room temperature (RT). Pituitary transcript expression was analyzed with single-cell RNA-seq. HFD-fed mice gained &amp;gt;20 g by 12 wks, showing increased serum leptin (1.8-2X), insulin (2-8X) and IL-6 (4-6X), decreased glucose clearance after a glucose challenge and decreased respiratory quotient indicating fat burning. Activity was unaffected by HFD. Rank plot analyses showed reduced amplitude GH pulses in HFD females fed at RT (15 wks), but not in mice fed at TN. Serum levels of other pituitary hormones were unaffected in HFD females. In HFD males, only serum TSH was elevated significantly (1.8X, 15 wks, TN). Analysis of the scRNA-seq data detected separate clusters representing each cell type. Two multihormonal cell clusters evident in control females mostly disappeared following HFD (15 wks, RT). At the threshold cutoff of avg Log2FC±0.5 with adj p&amp;lt;0.05, female somatotrope clusters showed reduced Pomc, Cga, and ribosomal proteins. Female lactotrope clusters exhibited decreased Gh mRNA (avg Log2FC -1.8 or -2.5) and galanin at 10 wks (TN). At 15 wks (TN), lactotrope clusters showed significant changes in 46 transcripts including reductions in Prl, 29 ribosomal proteins, galanin, and 3 transcriptional regulators. Notably, this cluster showed an increase in synaptotagmin-4 (Syt4), which is also elevated in oxytocin neurons following a HFD. Stem cell clusters in females were strongly impacted by HFD after 15 weeks (TN) with 94 reduced transcripts of which 48 were involved in cytoplasmic translation and ribosome biogenesis and &amp;gt;20 were involved with signaling and cell differentiation. In males, whereas changes in most clusters fell below the threshold cutoffs, stem cell clusters had 13 reduced transcripts after 10 or 15 weeks, most of which involved immune system processes including defense responses and antigen processing and presentation. The GH deficiency in mice fed under thermoneutral conditions was not as severe as that reported by Luque and Kineman, perhaps due to differences in strain, sex, and/or the environmental temperature. The reduced expression of multihormonal clusters, Gh by lactotropes and corticotropes, and Cga and Pomc by somatotropes suggests that HFD may reduce plasticity and activity of progenitor cells in the pituitary. The changes in lactotropes and somatotropes also indicate that HFD may compromise ribosome function and cytoplasmic translation. The reduced transcriptome in stem cells in both males and females suggests HFD interference with cell differentiation and pituitary plasticity as well as dysfunctional immune defense responses. Presentation: Thursday, June 15, 2023

Molecular basis of signal transduction mediated by the human GIPR splice variants

Glucose-dependent insulinotropic polypeptide receptor (GIPR) is a potential drug target for metabolic disorders. It works with glucagon-like peptide-1 receptor and glucagon receptor in humans to maintain glucose homeostasis. Unlike the other two receptors, GIPR has at least 13 reported splice variants (SVs), more than half of which have sequence variations at either C or N terminus. To explore their roles in endogenous peptide-mediated GIPR signaling, we determined the cryoelectron microscopy (cryo-EM) structures of the two N terminus-altered SVs (referred as GIPR-202 and GIPR-209 in the Ensembl database, SV1 and SV2 here, respectively) and investigated the outcome of coexpressing each of them in question with GIPR in HEK293T cells with respect to ligand binding, receptor expression, cAMP (adenosine 3,5-cyclic monophosphate) accumulation, β-arrestin recruitment, and cell surface localization. It was found that while both N terminus-altered SVs of GIPR neither bound to the hormone nor elicited signal transduction per se, they suppressed ligand binding and cAMP accumulation of GIPR. Meanwhile, SV1 reduced GIPR-mediated β-arrestin 2 responses. The cryo-EM structures of SV1 and SV2 showed that they reorganized the extracellular halves of transmembrane helices 1, 6, and 7 and extracellular loops 2 and 3 to adopt a ligand-binding pocket-occupied conformation, thereby losing binding ability to the peptide. The results suggest a form of signal bias that is constitutive and ligand-independent, thus expanding our knowledge of biased signaling beyond pharmacological manipulation (i.e., ligand specific) as well as constitutive and ligand-independent (e.g., SV1 of the growth hormone-releasing hormone receptor).

GHRH Neurons from the Ventromedial Hypothalamic Nucleus Provide Dynamic and Sex-Specific Input to the Brain Glucose-Regulatory Network.

The ventromedial hypothalamic nucleus (VMN) controls glucose counter-regulation, including pituitary growth hormone (GH) secretion. VMN neurons that express the transcription factor steroidogenic factor-1/NR5A1 (SF-1) participate in glucose homeostasis. Research utilized in vivo gene knockdown tools to determine if VMN growth hormone-releasing hormone (Ghrh) regulates hypoglycemic patterns of glucagon, corticosterone, and GH outflow according to sex. Intra-VMN Ghrh siRNA administration blunted hypoglycemic hypercorticosteronemia in each sex, but abolished elevated GH release in males only. Single-cell multiplex qPCR showed that dorsomedial VMN (VMNdm) Ghrh neurons express mRNAs encoding Ghrh, SF-1, and protein markers for glucose-inhibitory (γ-aminobutyric acid) or -stimulatory (nitric oxide; glutamate) neurotransmitters. Hypoglycemia decreased glutamate decarboxylase67 (GAD67) transcripts in male, not female VMNdm Ghrh/SF-1 neurons, a response that was refractory to Ghrh siRNA. Ghrh gene knockdown prevented, in each sex, hypoglycemic down-regulation of Ghrh/SF-1 nerve cell GAD65 transcription. Ghrh siRNA amplified hypoglycemia-associated up-regulation of Ghrh/SF-1 neuron nitric oxide synthase mRNA in male and female, without affecting glutaminase gene expression. Ghrh gene knockdown altered Ghrh/SF-1 neuron estrogen receptor-alpha (ERα) and ER-beta transcripts in hypoglycemic male, not female rats, but up-regulated GPR81 lactate receptor mRNA in both sexes. Outcomes infer that VMNdm Ghrh/SF-1 neurons may be an effector of SF-1 control of counter-regulation, and document Ghrh modulation of hypoglycemic patterns of glucose-regulatory neurotransmitter along with estradiol and lactate receptor gene transcription in these cells. Co-transmission of glucose-inhibitory and -stimulatory neurochemicals of diverse chemical structure, spatial, and temporal profiles may enable VMNdm Ghrh neurons to provide complex dynamic, sex-specific input to the brain glucose-regulatory network.

Distinct physiological characteristics and altered glucagon signaling in GHRH knockout mice: Implications for longevity.

Our previous research has demonstrated that mice lacking functional growth hormone-releasing hormone (GHRH) exhibit distinct physiological characteristics, including an extended lifespan, a preference for lipid utilization during rest, mild hypoglycemia, and heightened insulin sensitivity. They also show a further increase in lifespan when subjected to caloric restriction. These findings suggest a unique response to fasting, which motivated our current study on the response to glucagon, a key hormone released from the pancreas during fasting that regulates glucose levels, energy expenditure, and metabolism. Our study investigated the effects of an acute glucagon challenge on female GHRH knockout mice and revealed that they exhibit reduced glucose production, likely due to suppressed gluconeogenesis. However, these mice showed an increase in energy expenditure. We also observed alterations in pancreatic islet architecture, with smaller islets and a reduction of insulin-producing beta cells but no changes in glucagon-producing alpha cells. Additionally, the analysis of hepatic glucagon signaling showed a decrease in glucagon receptor expression and phosphorylated CREB. In conclusion, our findings suggest that the unique metabolic phenotype observed in these long-lived mice may be partly explained by changes in glucagon signaling. Further exploration of this pathway may lead to new insights into the regulation of longevity in mammals.

Ghrelin Amplifies the Nicotine-Induced Release of Dopamine in the Bed Nucleus of Stria Terminalis (BNST).

Ghrelin is an orexigenic neuropeptide that is known for stimulating the release of growth hormone (GH) and appetite. In addition, ghrelin has been implicated in addiction to drugs such as nicotine. Nicotine is the principal psychoactive component in tobacco and is responsible for the reward sensation produced by smoking. In our previous in vitro superfusion studies, it was demonstrated that ghrelin and nicotine stimulate equally the dopamine release in the rat amygdala, and ghrelin amplifies the nicotine-induced dopamine release in the rat striatum. However, less attention was paid to the actions of ghrelin and nicotine in the bed nucleus of the stria terminalis (BNST). Therefore, in the present study, nicotine and ghrelin were superfused to the BNST of male Wistar rats, and the dopamine release from the BNST was measured in vitro. In order to determine which receptors mediate these effects, mecamylamine, a non-selective nicotinic acetylcholine receptor (nAchR) antagonist, and GHRP-6, a selective growth hormone secretagogue receptor (GHS-R1A) antagonist, were also superfused to the rat BNST. Nicotine significantly increased the release of dopamine, and this effect was significantly inhibited by mecamylamine. Ghrelin increased dopamine release even more significantly than nicotine did, and this effect was significantly inhibited by GHRP-6. Moreover, when administered together, ghrelin significantly amplified the nicotine-induced release of dopamine in the BNST, and this additive effect was reversed partly by mecamylamine and partly by GHRP-6. Therefore, the present study provides a new base of evidence for the involvement of ghrelin in dopamine signaling implicated in nicotine addiction.

Role and molecular mechanism of ghrelin in degenerative musculoskeletal disorders.

Ghrelin is a brain-gut peptide, and the first 28-peptide that was found in the gastric mucosa. It has a growth hormone (GH)-releasing hormone-like effect and can potently promote the release of GH from pituitary GH cells; however, it is unable to stimulate GH synthesis. Therefore, ghrelin is believed to play a role in promoting bone growth and development. The correlation between ghrelin and some degenerative diseases of the musculoskeletal system has been reported recently, and ghrelin may be one of the factors influencing degenerative pathologies, such as osteoporosis, osteoarthritis, sarcopenia and intervertebral disc degeneration. With population ageing, the risk of health problems caused by degenerative diseases of the musculoskeletal system gradually increases. In this article, the roles of ghrelin in musculoskeletal disorders are summarized to reveal the potential effects of ghrelin as a key target in the treatment of related bone and muscle diseases and the need for further research.

Combined effects of crowding stress and low salinity on GH/IGF axis, antioxidant response, and HPI axis in largemouth bass (Micropterus salmoides) larvae

The present study aimed to determine if low salinity could mitigate negative effects of crowding stress on freshwater largemouth bass (Micropterus salmoides). To the end, larvae were subjected to crowding stress (CS) or low salinity (LS, 0.5‰), alone or in combination for 28 days. Growth, antioxidant capacity and stress response were investigated. CS significantly reduced body weight, total antioxidant capacity (TAC) and catalase (CAT) activity in the brain and head kidney, TAC and superoxide dismutase (SOD) activity in the liver, and increased cortisol levels in the whole body, suggesting negative effects of CS on fish. Contrarily, LS promoted body weight, body length and condition factor, and reduced MDA contents in the liver and head kidney and whole-body cortisol levels. Increases in TAC and CAT activity in the brain, SOD and CAT activities in the liver, and TAC, SOD and CAT activities in the head kidney were also observed in the larvae subjected to LS. The results indicated that LS promoted growth and antioxidant capacity and reduced stress response, which was also observed in fish subjected to CS. In order to elucidate the related molecular mechanisms, gene expression in the growth hormone/insulin-like growth factor-I (GH/IGF) axis, NF-E2-related factor 2 (Nrf2) pathway, and hypothalamus–pituitary–interrenal (HPI) axis were examined. We found that CS + LS up-regulated growth hormone release hormone gene (ghrh), growth hormone gene (gh), and hormone receptor gene (ghra) in the brain and ghra and insulin-like growth factor genes (igf1 and igf2b) in the liver compared with CS alone. The mRNA levels of Nrf2 pathway related genes were sharply enhanced by CS but were maintained relative constant by CS + LS in the brain and liver compared with the control. In the head kidney, CS + LS up-regulated Nrf2 pathway related genes compared with CS alone. HPI axis related genes tended to be up-regulated by CS but remain unchanged by CS + LS compared with the control. LS and CS + LS down-regulated both genes encoding cytochrome P450 enzymes (cyp17a1 and cyp11c1) which are rate-limiting enzymes for cortisol synthesis compare with the control and CS, respectively. Taken together, the present results for the first time provide a feasible suggestion for culture of largemouth bass larvae at high stocking density in saline waters.

Characterization of Somatotrope Cell Expansion in Response to GHRH in the Neonatal Mouse Pituitary.

In humans and mice, loss-of-function mutations in growth hormone-releasing hormone receptor (GHRHR) cause isolated GH deficiency. The mutant GHRHR mouse model, GhrhrLit/Lit (LIT), exhibits loss of serum GH, but also fewer somatotropes. However, how loss of GHRH signaling affects expansion of stem and progenitor cells giving rise to GH-producing cells is unknown. LIT mice and wild-type littermates were examined for differences in proliferation and gene expression of pituitary lineage markers by quantitative reverse transcription polymerase chain reaction and immunohistochemistry at postnatal day 5 (p5) and 5 weeks. At p5, the LIT mouse shows a global decrease in pituitary proliferation measured by proliferation marker Ki67 and phospho-histone H3. This proliferative defect is seen in a pituitary cell expressing POU1F1 with or without GH. SOX9-positive progenitors show no changes in proliferation in p5 LIT mice. Additionally, the other POU1F1 lineage cells are not decreased in number; rather, we observe an increase in lactotrope cell population as well as messenger RNA for Tshb and Prl. In the 5-week LIT pituitary, the proliferative deficit in POU1F1-expressing cells observed neonatally persists, while the number and proliferative proportion of SOX9 cells do not appear changed. Treatment of cultured pituitary explants with GHRH promotes proliferation of POU1F1-expressing cells, but not GH-positive cells, in a mitogen-activated protein kinase-dependent manner. These findings indicate that hypothalamic GHRH targets proliferation of a POU1F1-positive cell, targeted to the somatotrope lineage, to fine tune their numbers.

Alveolar epithelial cell growth hormone releasing hormone receptor in alveolar epithelial inflammation

Purpose: Growth hormone-releasing hormone (GHRH) is a 44-amino acid peptide that regulates growth hormone (GH) secretion. We hypothesized that GHRH receptor (GHRH-R) in alveolar type 2 (AT2) cells could modulate pro-inflammatory and possibly subsequent pro-fibrotic effects of lipopolysaccharide (LPS) or cytokines, such that AT2 cells could participate in lung inflammation and fibrosis. Methods: We used human alveolar type 2 (iAT2) epithelial cells derived from induced pluripotent stem cells (iPSC) to investigate how GHRH-R modulates gene and protein expression. We tested iAT2 cells’ gene expression in response to LPS or cytokines, seeking whether these mechanisms caused endogenous production of pro-inflammatory molecules or mesenchymal markers. Quantitative real-time PCR (RT-PCR) and Western blotting were used to investigate differential expression of epithelial and mesenchymal markers. Result: Incubation of iAT2 cells with LPS increased expression of IL1-β and TNF-α in addition to mesenchymal genes, including ACTA2, FN1 and COL1A1. Alveolar epithelial cell gene expression due to LPS was significantly inhibited by GHRH-R peptide antagonist MIA-602. Incubation of iAT2 cells with cytokines like those in fibrotic lungs similarly increased expression of genes for IL1-β, TNF-α, TGFβ-1, Wnt5a, smooth muscle actin, fibronectin and collagen. Expression of mesenchymal proteins, such as N-cadherin and vimentin, were also elevated after prolonged exposure to cytokines, confirming epithelial production of pro-inflammatory molecules as an important mechanism that might lead to subsequent fibrosis. Conclusion: iAT2 cells clearly expressed the GHRH-R. Exposure to LPS or cytokines increased iAT2 cell production of pro-inflammatory factors. GHRH-R antagonist MIA-602 inhibited pro-inflammatory gene expression, implicating iAT2 cell GHRH-R signaling in lung inflammation and potentially in fibrosis.

Growth hormone-releasing hormone antagonist MIA-602 inhibits inflammation induced by SARS-CoV-2 spike protein and bacterial lipopolysaccharide synergism in macrophages and human peripheral blood mononuclear cells.

COVID-19 is characterized by an excessive inflammatory response and macrophage hyperactivation, leading, in severe cases, to alveolar epithelial injury and acute respiratory distress syndrome. Recent studies have reported that SARS-CoV-2 spike (S) protein interacts with bacterial lipopolysaccharide (LPS) to boost inflammatory responses in vitro, in macrophages and peripheral blood mononuclear cells (PBMCs), and in vivo. The hypothalamic hormone growth hormone-releasing hormone (GHRH), in addition to promoting pituitary GH release, exerts many peripheral functions, acting as a growth factor in both malignant and non-malignant cells. GHRH antagonists, in turn, display potent antitumor effects and antinflammatory activities in different cell types, including lung and endothelial cells. However, to date, the antinflammatory role of GHRH antagonists in COVID-19 remains unexplored. Here, we examined the ability of GHRH antagonist MIA-602 to reduce inflammation in human THP-1-derived macrophages and PBMCs stimulated with S protein and LPS combination. Western blot and immunofluorescence analysis revealed the presence of GHRH receptor and its splice variant SV1 in both THP-1 cells and PBMCs. Exposure of THP-1 cells to S protein and LPS combination increased the mRNA levels and protein secretion of TNF-α and IL-1β, as well as IL-8 and MCP-1 gene expression, an effect hampered by MIA-602. Similarly, MIA-602 hindered TNF-α and IL-1β secretion in PBMCs and reduced MCP-1 mRNA levels. Mechanistically, MIA-602 blunted the S protein and LPS-induced activation of inflammatory pathways in THP-1 cells, such as NF-κB, STAT3, MAPK ERK1/2 and JNK. MIA-602 also attenuated oxidative stress in PBMCs, by decreasing ROS production, iNOS and COX-2 protein levels, and MMP9 activity. Finally, MIA-602 prevented the effect of S protein and LPS synergism on NF-кB nuclear translocation and activity. Overall, these findings demonstrate a novel antinflammatory role for GHRH antagonists of MIA class and suggest their potential development for the treatment of inflammatory diseases, such as COVID-19 and related comorbidities.

Abstract P2192: Growth Hormone-releasing Hormone Receptor Antagonist Attenuates Cardiopulmonary Injury Induced By A Bsl2 Rvsv-sars-cov-2-s Virus Mimic Of Sars-cov-2 Infectivity

Background: COVID-19 causes severe pulmonary injury that can lead to acute respiratory distress syndrome. Growth hormone-releasing hormone receptor (GHRH-R) and its splice variant are expressed in murine and human lung and heart. GHRH-R antagonist, MIA-602, has been shown to modulate cellular immune responses to bleomycin lung injury and decrease inflammation in models of sarcoid granuloma. Using the BSL2-friendly rVSV-SARS-CoV-2-S of K18 hACE2tg mice to mimic native SARS-CoV-2 infection, we tested our hypothesis that MIA-602 attenuates cardiopulmonary injury in this COVID-19 model. Methods: Male and female K18 hACE2tg mice were inoculated with SARS-CoV-2 Washington (WA-1) native strain, recombinant VSV-SARS-CoV-2-Spike virus (rVSV-SARS-CoV-2-S), or PBS and lung viral load, weight loss and histopathology compared between groups (N=5-8). K18 h ACE2 tg mice infected with rVSV-SARS-CoV-2-S were subject to daily subcutaneous injections of 10 μg MIA-602 or vehicle starting at 24h post-infection. Pulmonary function was measured via whole-body plethysmography on day 0, day 3, and day 5 (n=7). Five days after viral infection mice were sacrificed; and blood and tissues collected for histopathological analyses, H&amp;E staining and ICAM-1 immunohistochemistry. T-test or One-way ANOVA-test was used for statistical analysis. Results: Native SARS-CoV-2 and rVSV-SARS-CoV-2-S presented with similar patterns of weight loss, infectivity (~60%) and histopathologic changes. Daily treatment with MIA-602 ameliorated weight loss, reduced lung perivascular inflammation and pneumonia, and decreased lung/heart ICAM-1 expression compared to vehicle. MIA-602 rescued respiratory rate, increased expiratory parameters (Te, PEF, EEP) and mitigated dysregulated measures of airway obstruction (Penh and Rpef) compared to vehicle. Conclusions: rVSV-SARS-CoV-2-S is an accurate and safe alternative to native SARS-CoV-2 for preclinical studies. Daily treatment with the synthetic peptide GHRH-R antagonist MIA-602 attenuates pulmonary dysfunction and heart inflammation in this new preclinical mouse model of COVID-19 pneumonia. We hypothesize that the molecular mechanism involves anti-inflammatory actions of MIA-602.

Clinical, laboratory and ultrasonographic findings at baseline predict long-term outcome of polymyalgia rheumatica: a multicentric retrospective study

To assess the rate of PMR who, during the follow-up, undergo a diagnostic shift as well as to assess which clinical, laboratory and US findings are associated to a diagnostic shift and predict the long-term evolution of PMR. All PMR followed-up for at least 12 months were included. According to the US procedures performed at diagnosis, patients were subdivided into four subgroups. Clinical data from follow-up visits at 12, 24, 48 and 60 months, including a diagnostic shift, the number of relapses and immunosuppressive and steroid treatment, were recorded. A total of 201 patients were included. During the follow-up, up to 60% had a change in diagnosis. Bilateral LHBT was associated with persistence in PMR diagnosis, whereas GH synovitis and RF positivity to a diagnostic shift. Patients undergoing diagnostic shift had a higher frequency of GH synovitis, shoulder PD, higher CRP, WBC, PLT and Hb and longer time to achieve remission, while those maintaining diagnosis had bilateral exudative LHBT and SA-SD bursitis, higher ESR, lower Hb and shorter time to remission. Cluster analysis identified a subgroup of older patients, with lower CRP, WBC, PLT and Hb, lower PD signal or peripheral synovitis who had a higher persistence in PMR diagnosis, suffered from more flares and took more GCs. Most PMR have their diagnosis changed during follow-up. The early use of the US is associated with a lower dosage of GCs. Patients with a definite subset of clinical, laboratory and US findings seem to be more prone to maintain the diagnosis of PMR.

Analysis of Serum Ghrelin Levels and BMI in Obese and Non-Obese Subjects

Obesity is excessive body fat and was associated with the importance of metabolic and endocrine problems in somatotropic secretion in functional obesity. Ghrelin is an acylated peptide hormone produced by the stomach, which is a mediator of the growth hormone secretory receptor. The activity of ghrelin stimulates the release of growth hormone, and appetite and stimulates the metabolism of carbohydrates. Circulating ghrelin levels in healthy people increase during fasting and decrease after meals. This study aims to analyze the difference in ghrelin levels among obese and non-obese subjects. A cross-sectional design research was conducted in August 2022. The samples consisted of obese and non-obese subjects based on Body Mass Index (BMI). Ghrelin levels were measured using the Enzyme-Linked Immunosorbent Assay (ELISA) method. The data were statistically analyzed using the Mann-Whitney and Spearman tests. p&lt;0.05 was reported significant. The samples consisted of 80 obese and non-obese subjects, 39 males and 41 females. There was no difference in ghrelin serum levels in the obese group (1.45±2 ng/mL) compared to the non-obese group (0.67±0.25 ng/mL) with p =0.233 (p&gt;0.05). There was a positive correlation between ghrelin levels and BMI (r=0.247). There was no difference in ghrelin levels between the obese group and the non-obese group, and there was a positive correlation between ghrelin levels and BMI. A higher BMI would lead to higher ghrelin levels.

Neonatal malnutrition impacts fibroblast growth factor 21-induced neuron neurite outgrowth and growth hormone-releasing hormone secretion in neonatal mouse brain

Neonatal malnutrition is one of the most common causes of neurological disorders. However, the mechanism of action of the factors associated with neonatal nutrition in the brain remains unclear. In this study, we focused on fibroblast growth factor (FGF) 21 to elucidate the effects of malnutrition on the neonatal brain. FGF21 is an endocrine factor produced by the liver during lactation which is the main source of nutrition during the neonatal period. In this study, malnourishment during nursing mice induced decreased levels of Fgf21 mRNA in the liver and decreased levels of FGF21 in the serum. RNA-seq analysis of neonatal mouse brain tissue revealed that FGF21 controlled the expression of Kalrn-201 in the neonatal mouse brain. Kalrn-201 is a transcript of Kalirin, a Ras homologous guanine nucleotide exchange factor at the synapse. In mouse neurons, FGF21 induced the expression of Kalirin-7 (a Kalirin isoform) by down-regulating Kalrn-201. FGF21-induced Kalirin-7 stimulated neurite outgrowth in Neuro-2a cells. FGF21 also induced Growth hormone-releasing hormone (GHRH) expression in Neuro-2a cells. Kalirin-7 and GHRH expression induced by FGF21 was altered by inhibiting the activity of SH2-containing tyrosine phosphatase (SHP2) which is located downstream of the FGF receptor (FGFR). Additionally, malnourished nursing induced intron retention of the SHP2 gene (Ptpn11), resulting in the alteration of Kalirin-7 and GHRH expression by FGF21 signaling. Ptpn11 intron retention is suggested to be involved in regulating SHP2 activity. Taken together, these results suggest that FGF21 plays a critical role in the induction of neuronal neurite outgrowth and GHRH secretion in the neonatal brain, and this mechanism is regulated by SHP2. Thus, Ptpn11 intron retention induced by malnourished nursing may be involved in SHP2 activity.

Resistance exercise stress: theoretical mechanisms for growth hormone processing and release from the anterior pituitary somatotroph.

Heavy resistance exercise (HRE) is the most effective method for inducing muscular hypertrophy and stimulating anabolic hormones, including growth hormone, into the blood. In this review, we explore possible mechanisms within the GH secretory pathway of the pituitary somatotroph, which are likely to modulate the flow of hormone synthesis and packaging as it is processed prior to exocytosis. Special emphasis is placed on the secretory granule and its possible role as a signaling hub. We also review data that summarize how HRE affects the quality and quantity of the secreted hormone. Finally, these pathway mechanisms are considered in the context of heterogeneity of the somatotroph population in the anterior pituitary.

Levels and diagnostic values of serum visceral adipose tissue-derived serine protease inhibitor and secreted frizzle-related protein 5 in children with idiopathic short stature

Abstract Background: Idiopathic short stature (ISS) is a common type of short stature. We aimed to analyze the diagnostic values of serum visceral adipose tissue-derived serine protease inhibitor (Vaspin) and secreted frizzle-related protein 5 (SFRP5) for ISS children. Methods: Sixty-five ISS children treated from February 2019 to June 2022 were selected as an ISS group, while another 65 healthy children receiving physical examination in the same period were selected as a healthy group. Their general data, physical development status, levels of serum Vaspin and SFRP5, and levels of serum growth hormone-releasing hormone (GHRH)/growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis-related indicators were compared. Results: The ISS group had lower body height, body weight, bone age, growth velocity and serum SFRP5 level and higher serum Vaspin level than those of the healthy group (P&lt;0.05). The levels of serum GHRH, GH and IGF-1 were lower in the ISS group than those in the healthy group (P&lt;0.05). Body height, body weight, bone age, growth velocity, and levels of GHRH, GH and IGF-1 were negatively correlated with serum Vaspin level (r&lt;0, P&lt;0.05) but positively correlated with serum SFRP5 level (r&gt;0, P&lt;0.05). The areas under the ROC curves of serum Vaspin and SFRP5 and their combination for the diagnosis of ISS were 0.871 [95% confidence interval (CI): 0.812-0.929], 0.880 (95% CI: 0.824-0.935) and 0.942 (95% CI: 0.907-0.977), respectively. Conclusions: Children with ISS have a higher level of serum Vaspin but a lower level of SFRP5, and the combined detection has a higher diagnostic value for ISS.