Gene expression of insulin-like growth factor-I and IGF-I receptor during wound healing in rats.

OBJECTIVE--To measure the time course of changes in the concentrations of insulin-like growth factor-I (IGF-I), IGF-I messenger RNA (mRNA), and IGF-I receptor mRNA during wound healing. DESIGN--Open experimental study. MATERIAL--40 male Sprague-Dawley rats, each weighing 300 g. INTERVENTION--Stainless steel wire mesh cylinders implanted in the subcutaneous tissue of the back. Five rats killed at each time point (1.5, 2, 3, 4, 5, 7, 11, and 18 weeks). MAIN OUTCOME MEASURES--Wet weight and concentrations of IGF-I mRNA, and IGF-I receptor mRNA of granulation tissue, and concentration of IGF-I in wound fluid. RESULTS--The wet weight of granulation tissue increased significantly between week 1.5 and weeks 4-5, and then decreased. IGF-I mRNA concentration (amol/microgram DNA) increased significantly (threefold) between week 1.5 and weeks 3-5, and decreased between weeks 5 and 7. The concentration of IGF-I receptor RNA remained constant throughout the study, and the concentration of IGF-I in wound fluid remained constant until week 8 and then increased to a higher level at weeks 11-18. CONCLUSION--There is a transient rise in the gene expression of IGF-I but not of IGF-I receptor mRNA during wound healing.     

Morbidity of major hepatic resections: a 100-case prospective study.

OBJECTIVE: To assess the morbidity and its main risk factors after major hepatic resection. DESIGN: Retrospective study of prospectively collected data. SETTING: University hospital, France. SUBJECTS: 100 consecutive patients who underwent major hepatic resections, 1989-95. INTERVENTIONS: Major hepatic resection, defined as resection involving 3 or more segments according to Couinaud's classification, in all cases. MAIN OUTCOME MEASUREs: All complications that affected outcome or prolonged hospital stay. Risk factors identified by univariate and multivariate analysis. RESULTS: 45 patients developed at least 1 complication and 7 died. The most common complications were: pleural effusion (n = 21), hepatic failure (n = 12), and ascites (n = 9). Univariate analysis showed that the following variables were significantly related to the morbidity: age >55 years, American Society of Anesthesiologists (ASA) grade II or more, bilirubin >80 micromol/L, alkaline phosphatase activity more than double the reference range, malignant tumours, abnormal liver parenchyma, simultaneous surgical procedures, operative time >4 hours, and perioperative blood transfusion > or =600 ml. The extent of resection did not correlate with postoperative complications. Multivariate analysis showed that volume of blood transfusion > or =600 ml and simultaneous surgical procedures were the most important independent risk factors for complicated outcome. CONCLUSIONS: The morbidity associated with major hepatic resections remains high, and the main determinants of outcome are intraoperative surgeon-related factors.     

Growth hormone receptor abundance in tibial growth plates of uremic rats: GH/IGF-I treatment

BACKGROUND: Children with chronic renal failure (CRF) exhibit growth retardation and a disturbed growth hormone/insulin-like growth factor-I (GH/IGF-I) axis. Treatment of children with CRF with GH or GH/IGF-I can partially restore linear growth. The molecular basis for decreased longitudinal growth is not known but may involve an impaired action of GH. METHODS: We used the growth-retarded uremic rat model to determine the abundance and distribution of GH receptors (GHRs) in the tibial epiphyseal growth plate and the influence of GH, IGF-I, or combined GH/IGF-I treatment. Pair-fed rats were used as the control. RESULTS: While all treatment regimes increased body length and weight in both rat groups, only GH/IGF-I treatment increased the total growth plate width. This involved an increase in cell number in the hypertrophic zone, which could also be induced by IGF-I alone. Immunohistochemical analysis showed that uremic rats had decreased abundance of GHRs in the proliferative zone, and only GH/IGF-I therapy could overcome this decrease. These data thus suggest that growth retardation in uremic rats is, at least in part, due to a decrease in GHR abundance in chondrocytes of the proliferative zone of the tibial growth plate. This decreased GHR abundance can be overcome by combined GH/IGF-I therapy, thus enhancing generation and proliferation of hypertrophic zone chondrocytes and increasing growth-plate width. CONCLUSION: These studies point to a mechanism for the growth retardation seen in children with CRF, and suggest that combined GH/IGF-I treatment may provide more effective therapy for these patients than GH alone.     

IGF-I receptor is required for the anabolic actions of parathyroid hormone on bone.

We showed that the IGF-IR-null mutation in mature osteoblasts leads to less bone and decreased periosteal bone formation and impaired the stimulatory effects of PTH on osteoprogenitor cell proliferation and differentiation. INTRODUCTION: This study was carried out to examine the role of IGF-I signaling in mediating the actions of PTH on bone. MATERIALS AND METHODS: Three-month-old mice with an osteoblast-specific IGF-I receptor null mutation (IGF-IR OBKO) and their normal littermates were treated with vehicle or PTH (80 microg/kg body weight/d for 2 wk). Structural measurements of the proximal and midshaft of the tibia were made by microCT. Trabecular and cortical bone formation was measured by bone histomorphometry. Bone marrow stromal cells (BMSCs) were obtained to assess the effects of PTH on osteoprogenitor number and differentiation. RESULTS: The fat-free weight of bone normalized to body weight (FFW/BW), bone volume (BV/TV), and cortical thickness (C.Th) in both proximal tibia and shaft were all less in the IGF-IR OBKO mice compared with controls. PTH decreased FFW/BW of the proximal tibia more substantially in controls than in IGF-IR OBKO mice. The increase in C.Th after PTH in the proximal tibia was comparable in both control and IGF-IR OBKO mice. Although trabecular and periosteal bone formation was markedly lower in the IGF-IR OBKO mice than in the control mice, endosteal bone formation was comparable in control and IGF-IR OBKO mice. PTH stimulated endosteal bone formation only in the control animals. Compared with BMSCs from control mice, BMSCs from IGF-IR OBKO mice showed equal alkaline phosphatase (ALP)(+) colonies on day 14, but fewer mineralized nodules on day 28. Administration of PTH increased the number of ALP(+) colonies and mineralized nodules on days 14 and 28 in BMSCs from control mice, but not in BMSCs from IGF-IR OBKO mice. CONCLUSIONS: Our results indicate that the IGF-IR null mutation in mature osteoblasts leads to less bone and decreased bone formation, in part because of the requirement for the IGF-IR in mature osteoblasts to enable PTH to stimulate osteoprogenitor cell proliferation and differentiation.     

Melanin concentrating hormone is a novel regulator of islet function and growth

Melanin concentrating hormone (MCH) is a hypothalamic neuropeptide known to play a critical role in energy balance. We have previously reported that overexpression of MCH is associated with mild obesity. In addition, mice have substantial hyperinsulinemia and islet hyperplasia that is out of proportion with their degree of obesity. In this study, we further explored the role of MCH in the endocrine pancreas. Both MCH and MCHR1 are expressed in mouse and human islets and in clonal beta-cell lines as assessed using quantitative real-time PCR and immunohistochemistry. Mice lacking MCH (MCH-KO) on either a C57Bl/6 or 129Sv genetic background showed a significant reduction in beta-cell mass and complemented our earlier observation of increased beta-cell mass in MCH-overexpressing mice. Furthermore, the compensatory islet hyperplasia secondary to a high-fat diet, which was evident in wild-type controls, was attenuated in MCH-KO. Interestingly, MCH enhanced insulin secretion in human and mouse islets and rodent beta-cell lines in a dose-dependent manner. Real-time PCR analyses of islet RNA derived from MCH-KO revealed altered expression of islet-enriched genes such as glucagon, forkhead homeobox A2, hepatocyte nuclear factor (HNF)4alpha, and HNF1alpha. Together, these data provide novel evidence for an autocrine role for MCH in the regulation of beta-cell mass dynamics and in islet secretory function and suggest that MCH is part of a hypothalamic-islet (pancreatic) axis.     

重组生长激素对应激状态下鼠肝生长激素受体mRNA表达及肝脏再生的影响

目的 初步探讨重组生长激素（ｒＧＨ）改善肝切除术后疲劳结合征（ＰＯＦ）的分子机制及对肝脏再生的影响。方法 采用半定量逆转录聚合酶链式反应（ＲＴ－ＰＣＲ）技术,分别对治疗组及对照组大鼠切肝４０％术后３,７ｄ生长激素受体ｍＲＮＡ（ＧＨＲｍＲＮＡ）的表达及相对肝重量（肝重／体重）进行研究。结果 手术宾３ｄ组ＧＨＲ ｍＲＮＡ表达量明显下降;治疗组术后３ｄ ＧＨＲｍＲＮＡ的表达术后７ｄ肝脏再生且明显增加（Ｐ     

Growth hormone receptor expression and function in meningiomas: effect of a specific receptor antagonist.

OBJECT: This study was undertaken to explore the effects of growth hormone (GH) and the GH-stimulated peptide insulin-like growth factor-1 (IGF-1) on the growth rate of meningiomas. METHODS: Polymerase chain reaction and ribonuclease protection assays were used to demonstrate that GH receptor messenger RNA was present in all 14 meningioma specimens studied, regardless of tumor grade. Both wild type (GHRwt) and a previously described exon 3 deletion isoform (GHRd3) of the GH receptor were identified in individual tumor specimens. The importance of the GH receptor was assessed using a GH receptor antagonist (B2036). Blockade of the GH receptor with B2036 reduced serum-induced DNA synthesis, as measured by thymidine incorporation, by 8 to 33% (mean 20%) in primary meningioma cultures. Tumors that expressed the GHRwt and GHRd3 isoforms, or a combination of the two, were all responsive to antagonist treatment. The importance of IGF- in stimulating meningioma cell growth was also assessed. It was found that IGF-1 increased thymidine incorporation in primary meningioma cultures in a dose-dependent manner: 1 ng/ml, 5 ng/ml, and 10 ng/ml resulted in increases in thymidine incorporation of 21%, 43%, and 176%, respectively, over baseline values. CONCLUSIONS: In these studies the authors demonstrate that activation of the GH/IGF-1 axis significantly increases the growth rate of meningiomas. Blockade of the GH receptor on tumor cells inhibited tumor growth. If these findings are confirmed in animal studies, agents that downregulate the GH/IGF-1 axis might represent a potential adjuvant therapy in the management of patients with meningioma.     

原发性肝癌癌旁组织生长激素受体的表达

目的了解原发性肝癌癌旁组织生长激素受体(GHR)的表达情况.方法采用放射配体法对32例原发性肝癌(HCC)的癌旁组织进行了GHR的检测,并以6例正常肝组织作为对照.结果在32例肝癌癌旁组织均检测到GHR的存在,癌旁组织GHR的受体最大结合容量(RT)值为32.7441±3.5106fmol/mg.protein,Kd为0.6109±0.1105nmol/L;与对照组肝组织相比,肝癌癌旁组织GRH的RT降低(P＜0.05),而Kd无显著性改变(P＞0.05).结论全部癌旁组织均表达GHR,在这些受体功能未明的情况下,rhGH在肝癌患者中的使用应慎重.     

Growth hormone and growth hormone-related mRNA in uremic rats: effect of a growth hormone secretagogue

In experimental animals, the decreased growth during mild uremia is not accompanied by a loss in the capacity of the pituitary gland to secrete growth hormone (GH). With the development of orally administered GH "secretagogues" (GHS), it might be possible to stimulate growth during uremia without injections. This study was designed to determine the effects of the GHS, L-163,255. Uremia was induced by 5/6 nephrectomy (NX). GHS was given orally, 3 mg/kg, twice a week. Four groups of animals included: (1) sham-operated, (2) sham-operated, pair-fed, (3) uremic (NX), and (4) uremic, GHS-treated (NX+GHS). Blood sampling was conducted via intra-atrial catheters, and GH was quantitated. Pituitary GH mRNA was measured by Northern blot, and liver GH receptor and insulin-like growth factor-I mRNAs by RNAase protection. Untreated NX animals had a specific decrease in the "mass" of the GH pulses. A burst of GH was induced by GHS, but the pulsatile pattern of GH secretion over 6 h was not affected. An increase or a return to non-uremic levels of GH-related mRNAs occurred after GHS. Thus, GHS stimulated an acute burst of GH secretion and increased specific mRNAs encoding GH-related proteins in uremic animals.     

GnRHR与EGFR在原发性肝癌组织中表达及意义

目的研究促性激素释放激素受体（GnRHR）和表皮生长因子受体（EGFR）在原发性肝癌组织中的表达及临床意义。方法应用免疫组织化SP及原位定量法,对30例原发性肝癌组织中GnRHR、EGFR的表达进行检测及半定量分析。结果在原发性肝癌各种不同分化的癌组织均显示不同程度的GnRHR和EGFR阳性免疫反应,原位定量显示GnRHR表达阳性27例（90.00%）,EGFR表达阳性15例（50.00%）,原位定量显示GnRHR的表达高分化13例、中分化9例、低分化5例,随着组织分化程度增高而增高,EGFR的表达高分化3例、中分化5例、低分化7例,随着组织分化程度增高而降低（P〈0.05）,并且GnRHR较EGFR阳性免疫反应强。结论 GnRHR与EGFR的表达量可能与原发性肝癌的发生及发展有关。     

MEPE is a novel regulator of growth plate cartilage mineralization

Matrix extracellular phosphoglycoprotein (MEPE) belongs to the SIBLING protein family which play key roles in biomineralization. Although the growth plates of MEPE-overexpressing mice display severe morphological disruption, the expression and function of MEPE in growth plate matrix mineralization remains largely undefined. Here we show MEPE and its cleavage product, the acidic serine aspartate-rich MEPE-associated motif (ASARM) peptide, to be localised to the hypertrophic zone of the growth plate. We also demonstrate that the phosphorylated (p)ASARM peptide inhibits ATDC5 chondrocyte matrix mineralization. Stable MEPE-overexpressing ATDC5 cells also had significantly reduced matrix mineralization in comparison to the control cells. Interestingly, we show that the addition of the non-phosphorylated (np)ASARM peptide promoted mineralization in the ATDC5 cells. The peptides and the overexpression of MEPE did not affect the differentiation of the ATDC5 cells. For a more physiologically relevant model, we utilized the metatarsal organ culture model. We show the pASARM peptide to inhibit mineralization at two stages of development, as shown by histological and μCT analysis. Like in the ATDC5 cells, the peptides did not affect the differentiation of the metatarsals indicating that the effects seen on mineralization are direct, as is additionally confirmed by no change in alkaline phosphatase activity or mRNA expression. In the metatarsal organ cultures, the pASARM peptide also reduced endothelial cell markers and vascular endothelial growth factor mRNA expression. Taken together these results show MEPE to be an important regulator of growth plate chondrocyte matrix mineralization through its cleavage to an ASARM peptide.     

Growth hormone and insulinlike growth factor 1 promote intestinal uptake and hepatic release of glutamine in sepsis.

OBJECTIVE: To study the effects of growth hormone (GH) and insulinlike growth factor 1 (IGF-1) on whole body and gastrointestinal (GI), hepatic, femoral, and renal glutamine (GLN) uptake and release in septic piglets. SUMMARY BACKGROUND DATA: The GI metabolism of GLN is impaired during sepsis, and this may contribute to a breakdown of the gut's mucosal barrier. GH treatment has produced increased GI GLN uptake in surgical stress. Little is known about the effects of GH and IGF-1 in sepsis. METHODS: Twenty-four piglets were randomized to three groups of eight each: a GH group received a bolus of 16 IU of Genotropin; an IGF-1 group received a continuous infusion of 1.3 mg/hour of IGF-1; and a control group received saline. After surgical preparation, sepsis was induced with live Escherichia coli bacteria. Using isotope technique, whole body turnover and organ-specific absolute uptake and release were measured before and 4 hours after sepsis. RESULTS: After sepsis, both GH and IGF-1 treatment increased GI GLN uptake compared with controls and induced hepatic release of GLN. GLN release from skeletal muscle was diminished in all groups after sepsis. Whole body GLN turnover was increased in the GH and IGF-1 groups compared with the controls, before and after sepsis. CONCLUSIONS: GH and IGF-1 treatment induced increased GI net uptake of GLN. GH and IGF-1 treatment also promoted absolute and net release of GLN from the liver. This release might facilitate increased GI uptake despite reduced hindleg release in the early phase of sepsis.     

Acceleration of hepatic regeneration with prior stress and growth hormone.

Laparotomy, carried out 6 hr prior to partial hepatectomy, accelerates the entire response curve of DNA precursor uptake in the regenerating liver. Pretreatment with bovine growth hormone, 6 hr prior to partial hepatectomy, accelerates slightly and elevates the level of DNA precursor uptake in regenerating liver, forming an early sharp peak. The effects of both stimulae administered concurrently in the same animal, are additive, resulting in a 6-hr acceleration of the appearance of the first wave, and an approximately 9-hr acceleration of the second wave of DNA precursor uptake during regeneration. In male rats without adrenocortical function (adrenalectomized-castrated) growth hormone still produces augmentation of DNA precursur uptake in regenerating liver.     

Modulation of growth hormone signal transduction in kidneys of streptozotocin-induced diabetic animals: effect of a growth hormone receptor antagonist

Growth hormone (GH) and IGFs have a long distinguished history in diabetes, with possible participation in the development of renal complications. The implicated effect of GH in diabetic end-stage organ damage may be mediated by growth hormone receptor (GHR) or postreceptor events in GH signal transduction. The present study investigates the effects of diabetes induced by streptozotocin (STZ) on renal GH signaling. Our results demonstrate that JAK2, insulin receptor substrate (IRS)-1, Shc, ERKs, and Akt are widely distributed in the kidney, and after GH treatment, there is a significant increase in phosphorylation of these proteins in STZ-induced diabetic rats compared with controls. Moreover, the GH-induced association of IRS-1/phosphatidylinositol 3-kinase, IRS-1/growth factor receptor bound 2 (Grb2), and Shc/Grb2 are increased in diabetic rats as well. Immunohistochemical studies show that GH-induced p-Akt and p-ERK activation is apparently more pronounced in the kidneys of diabetic rats. Administration of G120K-PEG, a GH antagonist, in diabetic mice shows inhibitory effects on diabetic renal enlargement and reverses the alterations in GH signal transduction observed in diabetic animals. The present study demonstrates a role for GH signaling in the pathogenesis of early diabetic renal changes and suggests that specific GHR blockade may present a new concept in the treatment of diabetic kidney disease.