DXM Treatment Research Articles

Long course of low-dose dexamethasone following or after bleomycin administration ameliorates pulmonary fibrosis.

DXM is widely used as an antifibrotic agent due to its protection of the lungs against fibrosis by inhibiting the production of inflammatory mediators. Many studies clearly indicated that the time point at which DXM treatment started, the dose and the duration of intervention are critical for exerting its antifibrotic effect. Exploring the role of DXM in the occurrence and development of PF at different stages is the fundamental purpose of this article. Lung fibrosis was persuaded in Sprague-Dawley rats by a single intratracheal BLM (5mg/kg) injection. This experiment was divided into two animal experiments and treated with DXM following or after bleomycin administration respectively. The biochemical, histopathological and molecular alterations were studied in the lung tissues. A long course of low-dose DXM had the ability to ameliorate PF induced by BLM via decreasing inflammation and improving oxidative stress through modulation of TGF-β/Smad, PI3K/Akt/mTOR and NF-κB signaling pathway. Long course of low-dose DXM intake following or after bleomycin administration both had therapeutic effects on pulmonary fibrosis.

The Effects and Mechanisms of Improvement of Hydroxysafflor Yellow A in Pulmonary Fibrosis

Purpose: To discuss the effects and mechanisms of improvement of Hydroxysafflor yellow A in pulmonary fibrosis by in vivo study. Material and Methods: In this study, dividing the C57BL/6 mice as 4 group, there were 10 mice in every group. Collecting the serum of difference groups and measuring the Hyp, SOD, MDA, TNF-α and IL-6 levels. Lung tissues were taken out and evaluating the pathology by HE staining and fibrosis degree by Masson staining. The relative proteins (α-SMA and E-cadherin) were measured by IHC and WB in lung tissues of difference groups. Results: With HSYA or DXM supplement, the Hyp, MDA, TNF-α and IL-6 concentrations significantly suppressed and SOD concentration significantly enhanced (P < 0.05, respectively). Compared with Sham group, the pathology injury and fibrosis degree of Model group were significantly up-regulation (P < 0.001, respectively); With HSYA or DXM treatment, the pathology injury and fibrosis degree of HSYA and DXM groups were significantly improved (P < 0.05, respectively). By IHC and WB assay, the α-SMA and E-cadherin proteins expressions of Model group were significantly differences (P < 0.001, respectively); however, the α-SMA and E-cadherin proteins expressions of HSYA and DXM groups were significantly improved with HSYA or DXM supplement (P < 0.05, respectively). Conclusion: HSYA improves pulmonary fibrosis by regulation α-SMA and E-cadherin in vivo study.

Dexamethasone primes adipocyte precursor cells for differentiation by enhancing adipogenic competency

AimDexamethasone (DXM) is a synthetic glucocorticoid whose effects in early and terminal adipogenesis have been addressed. In this study, we evaluated if DXM affects adipocyte precursor cells (APCs), priming them for further adipogenic differentiation. For this purpose, we analyzed APCs number and competency after DXM treatment. Materials and methodsAdult male rats were injected for 2 or 7 days with either DXM (30 μg/kg of weight, sc.) or vehicle. Stromal vascular fraction (SVF) cells from retroperitoneal adipose tissue (RPAT) were isolated to quantify APCs by flow cytometry (CD34+/CD45−/CD31−). Also, expression of competency markers (PPARγ2 and Zfp423) was assessed. Additionally, SVF cells from control rats were incubated with DXM (0.25 μM) alone or combined with a mineralocorticoid receptor (MR) antagonist (Spironolactone 10 μM) and/or a glucocorticoid receptor (GR) antagonist (RU486 1 μM) to assess APCs competency and adipocyte differentiation. Key findingsAPCs from 2 days DXM-treated rats showed increased expression of PPARγ2 and Zfp423 (competency markers), but did not affect APCs percentage by FACS analysis (CD34+/CD45−/CD31−). Additionally, we found that DXM treatment in SVF also increased APCs competency in vitro, predisposing APCs to further adipocyte differentiation. These effects on APCs were abrogated only when both, MR and GR, were blocked. SignificanceOverall, our results suggest that DXM primes APCs for differentiation mainly by enhancing Zfp423 and PPARγ2 expressions. Also, we showed that the inhibition of MR and GR was necessary for the complete abolishment of DXM effects.

398PD - Extending temozolomide longer than six cycles in glioblastoma: Results of the randomized GEINO-014 trial

BackgroundStandard treatment of glioblastoma (GBM) is focal radiation with concomitant and adjuvant temozolomide (TMZ) for 6 cycles. The GEINO-14-01 trial (NCT02209948) investigated the role of extending adjuvant TMZ to 12 cycles in a randomized multicenter study. MethodsBetween Aug/2014 and Nov/2018, 166 patients (p) were screened and 159 randomized to extend (80p) or not (79p) TMZ treatment to 12 cycles after proving lack of progression of the disease in the MRI performed before inclusion. The trial was stratified by MGMT status and presence or absence of residual disease (defined as a residual enhancement larger than 1cm on the MRI). The primary endpoint was differences in 6monthsPFS, secondary endpoints were differences in PFS, OS, toxicity, between arms and per stratification factors. ResultsMedian age was 60.4 (range 29-83), all p had ECOG≤1 and 86.2% were without DXM treatment. MGMT status: Met: 97 (61%) UnMet:62 (39%). RD yes: 83 (52.2%) and no: 76 (47.8%). At the time of the abstract report 3 patients are still on treatment or control without a documented progression and 5 patients have not been yet 6m in the study: 31 patients (19.5) are still free of progression and 60 patients (37.7%) are still alive. Median (m) PFS has been reached: 7.9 months (95%CI: 6.1-9.8) as well as mOS: 20.9 (95%CI: 17.6-24.1). A methylated status was a factor of better PFS (HR=0.29, 95% CI 0.46-0.95; p=0.029) and better OS (HR=0.43: 95% CI 0.28-0.66; p=0.000) as well as the absence of residual disease (PFS: HR=0.84: 95% CI=0.71-1.01; p=0.068; OS: HR=0.77, 95%CI 0.63-0.96; p=0.019). We didn’t find any difference in PFS (HR=1.02, 95%CI 0.85-1.21; p=0.82), or OS (HR=0.90; 0.73-1.11; p=0.34) on extending treatment with temozolomide longer than 6 cycles. Toxicity data and final results are expected for the congress. ConclusionsThere is no benefit of continuing TMZ treatment for more than 6 cycles in the adjuvant treatment of glioblastoma. Met status and absence of RD are factors of better SLP after adjuvant treatment. Supported by a Grant of the ISCIII: PI13/01751. Clinical trial identificationNCT02209948. Legal entity responsible for the studyGEINO (Grupo Español de Investigación en Neurooncologia). FundingSupported by a Grant of the ISCIII. DisclosureM.A.V. Salgado: Advisory / Consultancy: Lilly; Research grant / Funding (institution): Pfizer; Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: pharmamar; Advisory / Consultancy: eisai; Advisory / Consultancy: Celgene. All other authors have declared no conflicts of interest.

Ginsenoside Rg1 abolish imiquimod-induced psoriasis-like dermatitis in BALB/c mice via downregulating NF-κB signaling pathway.

This animal experiment was framed to evaluate the beneficial effect of ginsenoside Rg1 (GRg1) against imiquimod (IMQ)-induced psoriasis-like dermatitis model to reveal the underpinning mechanism. Fifty healthy BALB/c mice were divided into five groups as control, GRg1, IMQ induced, oral treatment of GRg1 (50mg/kg), or dexamethasone (DXM; 10mg/kg) in IMQ-induced mice. Treatment with GRg1 or DXM significantly mitigates (p<.01) psoriasis area severity index (PASI) score, skin thickness, lipid peroxidation, and inflammatory markers (IL-23, 22, 17A, 1β, and TNF-α). Moreover, administration of GRg1 or DXM considerably reversed the morphological changes induced by IMQ with improved (p<.01) antioxidant activity (SOD, CAT). In addition, a marked downregulation (p<.01) of protein expressions of pIκB and NF-κB p65 (NF-κB signaling pathway) were noted in GRg1 group. Collectively, GRg1 or DXM treatment significantly abolishes IMQ-induced psoriasis-like dermatitis by lowering PASI score, inflammation through downregulating NF-κB signaling pathway. PRACTICAL APPLICATIONS: This is the very first study to explore the efficacy of ginsenoside Rg1 (GRg1) against IMQ-induced psoriasis in the mice model to reveal the underpinning mechanism. The results clearly showed that GRg1 potent anti-psoriasis activity by lowering PASI score, inflammation through downregulating NF-κB signaling pathway. Hence, this study helps in the development of novel nutraceutical/functional food against psoriasis and thus could improve the quality of life in psoriasis patients. However, further clinical trials are needed to justify the above results before developing a commercial functional food using GRg1 against psoriasis.

Curcumin ameliorated ventilator-induced lung injury in rats

BackgroundCurcumin (CUR) is a Chinese medicine monomer with antioxidant and anti-inflammatory properties. The aim of this study was to investigate the effects and mechanisms of CUR treatment on ventilator-induced lung injury (VILI) in rats. MethodsTotal 50 SD rats were divided into five groups: sham, VILI, VILI+CUR-50 (CUR 50 mg/kg pretreated intraperitoneal), VILI+CUR-200 (CUR 200 mg/kg pretreated intraperitoneal) and VILI + DXM (5 mg/kg pretreated intraperitoneal). The morphology and ultrastructure were observed by microscope and transmission electron microscope. The wet to dry ratio, protein concentration in bronchoalveolar lavage fluid (BALF), evans blue dye (EBD) content, nuclear factor kappa B (NF-κB) activity, myeloperoxidase (MPO), malondialdehyde (MDA), xanthine oxidase (XO) and total antioxidative capacity (TAOC) levels were measured. ResultsHistological studies revealed that inflammatory cells infiltration and alveolar edema were significantly severe in VILI as compared to other groups. CUR-200 and DXM treatment reversed lung injury significantly. The wet to dry ratio, protein concentration in BALF, EBD content, MPO activity, tumor necrosis factor (TNF)-α level and NF-κB activity were significantly increased in VILI group as compared to other groups. CUR-200 and DXM treatment significantly suppressed permeability and inflammation induced by ventilation. Furthermore, the significantly higher MDA content in VILI could be markedly decreased by CUR-200 and DXM treatment while the levels of XO and TAOC were markedly recovered only by CUR (200 mg/kg) treatment after VILI. ConclusionCUR could inhibit the inflammatory response and oxidative stress during VILI, which is partly through NF-κB pathway.

Dextromethorphan Exhibits Anti-inflammatory and Immunomodulatory Effects in a Murine Model of Collagen-Induced Arthritis and in Human Rheumatoid Arthritis

Dextromethorphan (d-3-methoxy-17-methylmorphinan, DXM) is a commonly used antitussive with a favorable safety profile. Previous studies have demonstrated that DXM has anti-inflammatory and immunomodulatory properties; however, the effect of DXM in rheumatoid arthritis (RA) remains unknown. Herein, we found that DXM treatment attenuated arthritis severity and proinflammatory cytokine expression levels, including TNF-α, IL-6, and IL-17A, in paw tissues of CIA mice. DXM treatment also reduced serum TNF-α, IL-6, and IL-17A levels of CIA mice and patients with RA. DXM further decreased the production of anti-CII IgG, IFN-γ, and IL-17A in collagen-reactive CD4+ T cells extracted from the lymph nodes of CIA mice. In vitro incubation of bone marrow–derived dendritic cells with DXM limited CD4+ T-cell proliferation and inflammatory cytokine secretion. In conclusion, our results showed that DXM attenuated arthritis symptoms in CIA mice and significantly reduced proinflammatory cytokines in patients with RA, suggesting that it can be used as an anti-arthritic agent.

Repeated, high-dose dextromethorphan treatment decreases neurogenesis and results in depression-like behavior in rats.

Abuse of cough mixture is increasingly prevalent worldwide. Clinical studies showed that chronic consumption of cough mixture at high dosages may lead to psychiatric symptoms, especially affective disturbances, with the underlying mechanisms remain elusive. The present study aims at exploring the effect of repeated, high-dose dextromethorphan (DXM, a common active component of cough mixture) treatment on adult hippocampal neurogenesis, which is associated with pathophysiology of mood disturbances. After treatment with a high-dose of DXM (40 mg/kg/day) for 2 weeks, Sprague-Dawley rats showed increased depression-like behavior when compared to the control animals. Neurogenesis in the hippocampus was suppressed by DXM treatment, which was indicated by decreases in number of proliferative cells and doublecortin (an immature neuron marker)-positive new neurons. Furthermore, the dendritic complexity of the immature neurons was suppressed by DXM treatment. These findings suggest that DXM induces depression- and anxiety-like behavior and suppresses neurogenesis in rats. The current experimental paradigm may serve as an animal model for study on affective effect of cough mixture abuse, rehabilitation treatment options for abusers and the related neurological mechanisms.

Intrathecal dexamethasone and methotrexate treatment of neoplastic meningitis from solid tumors

Aim: Neoplastic meningitis (NM) from solid tumors is an advanced malignancy with poor prognosis. Intrathecal chemotherapy is a reliable treatment, and we have obtained some experiences in the treatment of NM with intrathecal dexamethasone and methotrexate (IT DXM and MTX). Methods: Retrospective study of 23 patients with NM from lung cancer ( n = 11), breast cancer ( n = 3), gastric cancer ( n = 1), malignant melanoma ( n = 1), unknown cancer ( n = 7) was conducted. Among these patients, eight received IT DXM and MTX treatment, and 15 patients were placed into a palliative care group. Overall survival (OS) was compared, and the patients' characteristics, symptoms, and some laboratory examinations were analyzed to find the risk factors affecting OS. Results: OS of IT DXM and MTX group was significantly longer than that of the palliative care group ( P = 0.01). The median survival (MS) of palliative care group was 7.53 weeks (5.50-9.57; n = 15), and of the IT DXM and MTX group, 28.63 weeks (12.50-44.75; n = 8); IT DXM and MTX prolonged the OS of NM patients (regression coefficient = −2.923), with odds ratio (OR) being 0.054 (0.09-0.323). Spinal nerves damage decreased the OS (regression coefficient = 1.595), with OR being 4.928 (1.382-17.579). Conclusion: IT DXM and MTX have prolonged the patients' MS, which could be used as a fundamental treatment of NM. Time of induction treatment should be flexible and individualized, and induction treatment could restart when central nervous system relapse. Patients with spinal nerves damage are apt to live shorter.

Effect of the denervation of porcine ovaries on dexamethasone-induced cyst formation

Previously, we have shown that the activity of noradrenergic nerve fibres increased and the steroid content changed in porcine ovaries with dexamethasone-(DXM-) induced polycystic status. To better understand the role of the ovarian nerves in the formation of cystic status, the morphology and steroidogenic activity of the ovaries of DXM-treated gilts after denervation of the gonads were investigated in this study. Ovarian denervation was performed on day 3 of the first studied oestrous cycle and then, on days 7-21 of the cycle, DXM was administered. Following neurectomy and DXM treatment, cysts, medium-sized follicles and corpora lutea were not present, while the number of small-sized follicles increased. Denervation and DXM application led to a reduction in the number of dopamine-β-hydroxylase- and/or neuropeptide Y-immunoreactive nerve fibres. The concentrations of progesterone, androstenedione, testosterone and oestradiol-17β in the follicular fluid and/or in the wall of small-sized follicles of the experimental gilts were lower than in the controls. A similar result was demonstrated for P450scc, 3β-HSD and P450arom protein contents in the small follicles. Our data showed that DXM was not able to stimulate the formation of cysts in denervated porcine ovaries, indicating that the ovarian peripheral nerves might participate in the aetiopathogenesis of polycystic status.

Dextromethorphan Attenuates LPS‐Induced Adhesion Molecule Expression in Human Endothelial Cells

This study examines the effect of Dextromethorphan (d-3-methoxy-17-methylmorphinan; DXM), a commonly used cough-suppressing drug, on the expression of VCAM-1 and ICAM-1 in human umbilical vein endothelial cells (HUVECs) stimulated with lipopolysaccharide (LPS). The effect of DXM on expression of cell adhesion molecules induced by LPS was evaluated by monocyte bindings in vitro and ex vivo and transmigration assays. The signaling pathways involved in the inflammation inhibitory effect of DXM were analyzed by Western blot and immunofluorescent stain. Pretreatment of HUVECs with DXM inhibited LPS-induced adhesion of THP-1 cells in vitro and ex vivo, and reduced transendothelial migration of these cells. Furthermore, treatment of HUVECs with DXM can significantly decrease LPS-induced expression of ICAM-1 and VCAM-1. DXM abrogated LPS-induced phosphorylation of ERK and Akt. The translocation of early growth response gene-1 (Egr-1), a downstream transcription factor involved in the mitogen-activated kinase (MEK)-ERK signaling pathway, was suppressed by DXM treatment. Furthermore, DXM inhibited LPS-induced IκBα degradation and nuclear translocation of p65. Dextromethorphan inhibits the adhesive capacity of HUVECs by reducing the LPS-induced ICAM-1 and VCAM-1 expression via the suppression of the ERK, Akt, and NF-κB signaling pathways. Thus, DXM is a potential anti-inflammatory therapeutic that may modulate atherogenesis.

A phase II multicentric study of sunitinib administered as upfront therapy in glioblastoma: A study by the GEINO group.

2045 Background: Sunitinib is a multitargeted tyrosine kinase inhibitor that has direct antitumor and antiangiogenesis activity through targeting VEGFR 1-2, PDGFR α-β, c-kit, bFGF, (CSF-1), FLT3 and RET. Experimental studies in GB mice showed angiogenic activity, prolonged survival and synergy with irradiation Methods: Eligible pts were ≤75 years with GB not amenable to resection, PS≥2, MMS ≥25. Treatment was sunitinib 37.5mg daily for 8 w before radiotherapy, during radiotherapy (60Gy, 6 w) and after radiotherapy until disease progression. Primary endpoint was overall response (OR) (RANO criteria) after 8 w of sunitinib treatment before radiotherapy. Secondary endpoints were % pts free of neurological deterioration before radiotherapy, % pts who completed radiotherapy, PFS, OS and 1-year survival. We used a Simon 2-stage design (12 →20) based on OR to calculate the number of patients needed to detect at least 10% of responses with α error of 0.05 and β error of 0.10. Twelve patients were included in the first phase and one response was needed to continue study accrual. Results: 12 pts were enrolled: 7 males, median age 65 years, PS≥1: 8pts, median MMS 26.5. Neurological deficit: 5pts, DXM treatment 10/12, non-EIDS 3/12. Treatment: 5 pts completed 8 w of therapy, 2pts completed 7 w, 4 pts ≤ 6w. Toxicity G3 and 4: diarrhea (1pt), asthenia (2pts), skin and EDDPP (2), mucositis (2), fatal CNS hemorrhage (1), hypercholesterolemia and hypertriglycemia (1). OR was 1/12 SD, 11/12 P; radiological response was SD in 5 pts but 4 pts progressed neurologically. Only 2 pts completed radiotherapy plus sunitinib. The only SD received treatment for 18 w. Median PFS was 7.5w (CI 95% 5.8-9.2), OS 16w (CI 95% 0.5-23.7), 1year OS: 0%. Conclusions: the trial was closed after the first stage due to lack of response. Sunitinib is an inactive agent in glioblastoma.

Diabetes protection and restoration of thymocyte apoptosis in NOD Idd6 congenic strains.

Type 1 diabetes in the nonobese diabetic (NOD) mouse is a multifactorial and polygenic disease. The NOD-derived genetic factors that contribute to type 1 diabetes are named Idd (insulin-dependent diabetes) loci. To date, the biological functions of the majority of the Idd loci remain unknown. We have previously reported that resistance of NOD immature thymocytes to depletion by dexamethazone (Dxm) maps to the Idd6 locus. Herein, we refine this phenotype using a time-course experiment of apoptosis induction upon Dxm treatment. We confirm that the Idd6 region controls apoptosis resistance in immature thymocytes. Moreover, we establish reciprocal Idd6 congenic NOD and B6 strains to formally demonstrate that the Idd6 congenic region mediates restoration of the apoptosis resistance phenotype. Analysis of the Idd6 congenic strains indicates that a 3-cM chromosomal region located within the distal part of the Idd6 region controls apoptosis resistance in NOD immature thymocytes. Together, these data support the hypothesis that resistance to Dxm-induced apoptosis in NOD immature thymocytes is controlled by a genetic factor within the region that also contributes to type 1 diabetes pathogenesis. We propose that the diabetogenic effect of the Idd6 locus is exerted at the level of the thymic selection process.

Dexamethasone decreases plasma levels of the prochiral fenbendazole and its chiral and achiral metabolites in sheep

1. The effect of co-administration of either short- or long-acting formulations of DXM on hepatic function and the plasma pharmacokinetic behaviour of prochiral fenbendazole (FBZ) and its metabolites was evaluated in sheep. 2. Neither DXM treatment markedly affected any of the biochemical markers of hepatic function tested. In contrast, both formulations significantly modified the plasma pharmacokinetic behaviour of FBZ and its metabolites. 3. Plasma FBZ concentrations and the associated area under the time-concentration curves were significantly lower, although the plasma detection period was longer (72 versus 48 h) in the DXM pretreated animals compared with those given FBZ alone. 4. DXM also appeared to alter the pattern of FBZ absorption, possibly through effects on abomasal pH. The shape of the plasma concentration-time curves for oxfendazole (OFZ) and fenbendazole sulphone (FBZSO 2) were similar to FBZ, raising the possibility that DXM treatment may have altered the liver biotransformation of the parent drug. 5. The concentrations of the (+) chiral metabolite of OFZ were significantly lower in DXM pretreated animals compared with those given FBZ alone. The trend was similar for the (−) antipode, although the differences between DXM pretreated and non-pretreated animals were not statistically significant.

A novel brain trauma model in the mouse: effects of dexamethasone treatment.

We describe a novel methodological approach for inducing cold lesion in the mouse as a model of human cortical contusion trauma. To validate its reproducibility and reliability, dexamethasone (Dxm) was repeatedly applied to demonstrate possible antioedematous drug effects. Following the induction of anaesthesia with halothane, the dura was exposed via trephination. Using a micromanipulator a pre-cooled (-78 degrees C) copper cylinder, 3 mm in diameter, was pressed down to a depth of 1 mm onto the dura for 30 s under microscopic control. The body temperature was held constant at 37 degrees C throughout the procedure. Blood pressure (BP), measured by a modified photosensor-monitored tail-cuff method, and acid-base status were not significantly different when analysed before and after cold lesion and prior to sacrifice. However, there was a marginal mixed respiratory and metabolic acidosis. The antioedematous action of Dxm was studied in four standard pre-and post-treatment paradigms: 2x0.5 mg/kg (II), 2x12.5 mg/kg (III) and 4x6.25 mg/kg (IV: 3x pre-, 1x post-treatment: V: 1x pre-, 3x post-treatment). Physiological saline injections served as controls. High doses of Dxm (III-V) significantly attenuated the cold-lesion-induced loss of body mass. Dxm treatment also resulted in a reduction of brain water content (III; P<0.05), and brain swelling (IV; P<0.05) in the lesioned hemisphere, relative to controls. In conclusion, we have characterized a novel cold lesion model in the mouse to mimic traumatic brain injury and the beneficial effect of Dxm treatment on the extent of brain oedema.

Fluorescein Fluorescence Hyperpolarization as an Early Kinetic Measure of the Apoptotic Process

The ability to identify apoptotic cells within a complex population is crucial in the research and diagnosis of normal physiology and disease states. The Cellscan mark S (CS-S) cytometer was used in this study to detect intracellular fluorescence intensity and polarization (FI and FP) in several well-established models of apoptosis: Following spontaneous apoptosis, as well as glucocorticoid or anti Fas-induced apoptosis, CS-S individual cell-based analysis revealed the appearance of a cell cluster characterized by low FI and high FP. Temporal analysis of annexine V binding and FP measurements following DXM treatment showed that hyperpolarization preceded phosphatidylserine appearance on the outer plasma membrane. The early increase in FP was found to be dose dependent and inversely related to cell diameter. Cell dehydration and alteration of plasma membrane transport properties, both occurring during early stages of apoptosis, may be involved in the phenomena of intracellular fluorescein hyper-polarization in apoptosis.

Alterations in carbohydrate metabolism by exogenous dexamethasone and corticosterone in post-hatched White Leghorn chicks.

1. Alterations in carbohydrate metabolism in terms of tissue glycogen contents, phosphorylase (EC 2.4.1.1) activity, hepatic glucose-6-phosphatase (6-6-Pase: EC 3.1.3.9) activity and blood glucose have been evaluated in 30-d-old White Leghorn chicks under induced chronic hypocorticalism (by dexamethasone: DXM) and hypercorticalism (by corticosterone: CORT). 2. DXM treatment showed increased tissue glycogen contents and hypoglycaemia with decreased phosphorylase activity while CORT treatment produced a reverse set of changes. 3. Both steroid treatments increased hepatic G-6-Pase activity. These observations have been taken to indicate a definite role for glucocorticoids in regulating carbohydrate metabolism in neonatal chicks. 4. It is suggested that hypo- or hyper-corticalism could influence carbohydrate metabolism by affecting the secretory/activity ratio of pancreatic hormones.

Gene expression of insulin-like growth factors (IGFs), the type 1 IGF receptor, and IGF-binding proteins in dexamethasone-induced fetal growth retardation.

Altered gene expression and/or actions of the insulin-like growth factors (IGFs) have been implicated in the mediation of both pre- and postnatal growth retardation secondary to glucocorticoid excess. To investigate this possibility, we assessed the gene expression of the IGFs, the type I IGF receptor, and IGF-binding proteins (IGFBPs) in 20-day gestation liver and lung of growth-retarded fetuses whose mothers were treated with dexamethasone (DXM; 100 micrograms, ip, daily) on gestation days 15-19 (gestation = 21-22 days). DXM treatment in dams produced fetal growth retardation without decreasing litter size (32% decrease in fetal body weight). Both fetal liver and lung demonstrated decreased wet weight (48% and 47%, respectively) and DNA content (65% and 51%, respectively) compared to control animals. Our results suggest that increased expression of IGFBP-1, and possibly IGFBP-2, is involved in mediating the marked growth retardation. As assessed by solution hybridization assays and Northern blot analysis, there was an 8.5-fold increase in IGFBP-1 mRNA expression in the livers of DXM-treated fetal animals compared to that in sham-injected controls (P less than 0.002). IGFBP-2 mRNA expression was also increased (60%) in fetal liver, whereas IGFBP-3 was decreased (57%). In fetal lung, IGFBP-1 transcript abundance was also higher in DXM-treated fetal animals. Serum concentrations of IGFBP-1, but not those of IGFBP-2, were increased (approximately 4-fold) in the DXM-treated fetuses, as quantified by [125I]IGF-I ligand blotting and IGFBP-2 immunoblotting. Because hypoinsulinemia increases the expression of IGFBP-1 and -2, serum insulin concentrations were measured and found to be decreased in the DXM-treated fetuses (24 microU/ml) compared to control values (72 microU/ml). Analysis of mRNA expression for IGF-I, IGF-II, and the type 1 receptor transcripts did not support a role for decreased IGF or IGF receptor expression in the etiology of DXM-mediated growth retardation. IGF-I was unchanged in both liver and lung, and IGF-II transcripts were increased by 31% in liver and unchanged in lung of DXM-treated fetal animals. Northern analysis of hepatic and lung poly(A) RNA demonstrated no evidence for independent regulation of specific-sized IGF transcripts. Further, type 1 IGF receptor RNA abundance increased 42% in fetal liver and was unchanged in lung. Because IGFBPs may modulate IGF action, these results suggest that increased IGFBP-1, and possibly IGFBP-2, expression may be of importance in the etiology of DXM-induced fetal growth retardation.