Growth hormone is not able to counteract osteopenia of rat cortical bone induced by Glucocorticoid with protracted effect

Osteopenia and inhibited longitudinal growth in childhood are serious side effects during glucocorticoid therapy. The effects of glucocorticoids on bone have been confirmed in animal experiments. Long-term glucocorticoid administration to rats results in reduced body weights, reduced bone growth (length and cross-sectional area), and bone strength. Glucocorticoid treatment also resulted in a reduced bending stress, indicating reduced bone quality. Growth hormone, on the other hand, increased body weights, bone dimensions, and bone strength. The aim of the present study was to evaluate if growth hormone administration would have an anabolic effect on rat bone when given to animals also receiving a high dosage of glucocorticoid. Five groups of female rats, 3.5 months old, were treated as follows: (1) saline control; (2) glucocorticoid (prednisolone: Delcortol 5 mg/kg/day); (3) growth hormone (recombinant human growth hormone 5 mg/kg/day); (4) glucocorticoid and growth hormone; and (5) food restriction, consisting of restricted access to food to reduce their weight gain to match that of the glucocorticoid injected rats. After 80 days of hormone administration the animals were sacrificed. The right femur was removed and tested biomechanically in a three-point bending procedure. The left femur was used for determination of bone dimensions. Biomechanical parameters (ultimate load and ultimate stiffness) were then normalized to diaphyseal cross-sectional diameters of the femur, giving the values of ultimate bending stress and Young's modulus. Results: administration of both hormones simultaneously could not reverse the decrease in body weights, bone length, and diameters, or the decreased bone strength induced by glucocorticoid administration. In conclusion, growth hormone cannot prevent cortical osteopenia in female rats induced by a high dose of glucocorticoid with protracted effect.     

经咽旁入路选择性切除大鼠垂体前叶的研究

目的研究经咽旁入路选择性的切除大鼠垂体前叶，以制备大鼠垂体前叶激素缺乏模型如生长激素（GH）缺乏模型。方法经腹侧咽旁入路，运用显微神经外科技术经基蝶骨底选择性地切除垂体前叶。然后采用竞争免疫沉淀法检测大鼠生长激素的含量，术后统计死亡率、成功率。结果切除垂体前叶后大鼠的死亡率为26．7％，成活率为73．3％，全切率为91％；成功制备大鼠模型的GH显著低于假手术组和对照组。结论运用显微外科技术可以成功的选择性的切除大鼠垂体前叶，制备出垂体前叶激素如生长激素缺乏的动物模型。     

中药生精冲剂对精索静脉曲张大鼠的治疗

目的：研究中药生精冲剂对大鼠精索静脉曲张的影响及疗效。方法：从80只SD雄性大鼠中随机抽出20只作为假手术组，余60只均建立精索静脉曲张病理模型后随机均分为模型组、生精冲剂组和克罗米芬组。造模后15d生精冲剂组和克罗米酚组分别给予生精冲剂4g/（kg·d）和克罗米芬20mg/（kg·d）灌胃，模型组和假手术组正常喂食。造模后45d放免法测定血清性激素（FSH、LH和T）及观察各组大鼠睾丸组织结构。结果：生精冲剂组大鼠光镜下睾丸组织结构优于模型组和克罗米芬组；血清FSH、LH生精冲剂组显著低于模型组和克罗米芬组（P〈0.05），而克罗米芬组显著高于其他3组。T在生精冲剂组、克罗米芬组和假手术组之间无显著差异，但均显著高于模型组（P〈0.05）。结论：中药生精冲剂对精索静脉曲张引起的睾丸损害有保护及修复作用，且可能优于克罗米芬。     

Diplotypes of the human serotonin 1B receptor promoter predict growth hormone responses to sumatriptan in abstinent alcohol-dependent men.

BACKGROUND: Some studies have associated alcohol dependence (AD) with the human serotonin (5-HT)(1B) receptor (HTR1B). This investigation explored the functional responsivity of HTR1B in abstinent AD men using a sumatriptan challenge, while measuring genetic heterogeneity in the HTR1B promoter. METHODS: Abstinent AD men (n = 27) and abstinent men without any alcohol use disorder (n = 19) were administered 6 mg of sumatriptan succinate, subcutaneously. Plasma samples collected over the following 2 hours were assayed for growth hormone (GH) concentrations. His DNA was genotyped for the A-161T and T-261G polymorphisms of the HTR1B promoter and diplotypes determined. RESULTS: Integrated GH responses were predicted by interactions of AD and promoter diplotypes, as well as subject ethnicity. The final model accounted for nearly 35% of the variance in GH responses. Post hoc evaluation revealed that AD was associated with a blunting of GH secretion only among individuals with the most common HTR1B diplotype (TT/TT). CONCLUSIONS: A blunting of GH responses in abstinent AD men was observed only among those with the most common HTR1B promoter diplotype. Less common promoter diplotypes appeared protective. Controlling for genetic background is a useful augmentation of case-control pharmacological challenge strategies designed to elucidate the psychobiology of AD and other complex disorders.     

促甲状腺素及其受体与骨质疏松关系的研究进展

骨质疏松症(OP)是严重威胁老年人身心健康的常见疾病。随着人口老年化,老年性骨质疏松症发病率逐年增加。近年来内分泌性骨质疏松日见增多,促甲状腺激素(TSH)及促甲状腺激素受体(TSHR)与骨量减少、骨质疏松的关系倍受关注。成骨细胞和破骨细胞上的促甲状腺激素受体的作用是造成这一作用的关键。而此过程还会受到2型碘化甲腺氨酸脱碘酶、肿瘤坏死因子(TNF)等的影响。同时促甲状腺激素受体存在基因多态性,对其功能存在不同程度的影响,也可能是造成骨质疏松的重要原因。通过对这个领域的深入研究为内分泌性骨质疏松的防治提供依据。     

重组人生长激素对荷人胃癌裸鼠移植瘤血管内皮生长因子表达的影响

目的研究重组人生长激素（rhGH）对生长激素受体（GHR）不同表达状态裸鼠人胃癌移植瘤生长及血管内皮生长因子（VEGF）表达的影响。方法采用免疫细胞化学染色法筛选出GHR阳性和阴性表达的细胞株各1株，分别接种于24只裸鼠皮下。将两种细胞接种裸鼠均随机分为对照组（0．9％NaCl，0．2ml／d）、低剂量rhGH组（0．5U·kg^-1·d^-1，0．2ml／d）和高剂量rhGH组（2．5U·kg^-1·d^-1，0．2mL／d）3组，每组8只，各组均连续给药14d，观察并记录裸鼠体重和肿瘤体积变化；采用酶联免疫吸附法测定各组裸鼠血清VEGF含量，免疫组织化学方法检测胃癌组织中VEGF蛋白表达，RT-PCR方法检测胃癌组织VEGFmRNA水平变化。结果筛选出GHR阳性表达的人胃癌细胞株SGC-7901和阴性表达的MKN-45。对于GHR^＋SGC-7901接种裸鼠，rhGH给药组皮下移植瘤体积较对照组增大（P〈0．05），且高剂量rhGH组促增长效应最为显著（P〈0．05），3组间体重差异无统计学意义（P〉0．05）；高剂量rhGH组的血清VEGF浓度为（252．94±15．32）ng／L，明显高于对照组的（49．94±5．73）ng／L和低剂量rhGH组的（167．60±9．54）ng／L（P〈0．05）；对照组VEGF表达为中度阳性，rhGH给药组呈强阳性；高剂量rhGH组肿瘤组织中VEGFmRNA相对表达量为0．6470±0．0447，明显高于对照组的0．3230±0．0258和低剂量rhGH组的0．4120±0．0351（P〈0．05）。对于GHR—MKN-45接种裸鼠，rhGH给药组体重明显大于对照组（P〈0．05）；肿瘤体积大小、血清VEGF水平、肿瘤组织VEGF蛋白及mRNA表达，3组间差异均无统计学意义（P〉0．05）。结论rhGH能促进GHR阳性表达的SGC-7901移植瘤生长，并促进VEGF表达增高；对于GHR阴性的MKN-45移植瘤，则没有表现出明显的促肿瘤生长及促VEGF表达效应。GHR存在可能是rhGH影响VEGF分泌的关键靶点。     

Pyridinium crosslinks of collagen as a marker of bone resorption rates in children and adolescents: Normal values and clinical application

The aim of our study was to establish normal values of urinary pyridinoline (Pyr) and deoxypyridinoline (DPyr) excretion for children aged 3–18 years, examine the biological variability of the marker, and assess its clinical value for pediatric patients with growth hormone deficiency. Pyr and DPyr was measured in first void urine samples from 692 healthy subjects (340 boys, 352 girls) by high-performance liquid chromatography. At sampling, age, body height, and weight was recorded for all individuals. Short-term variability in crosslinks excretion was examined in four healthy children. The clinical value of the marker was studied in seven patients with growth hormone (GH) deficiency. In childhood, crosslinks excretion exceeded normal adult values by about fivefold and declined during puberty. In the age range of 13–18 years, gender-related differences in Pyr and DPyr levels were observed, presumably resulting from the earlier onset of puberty in girls. Urinary levels of Pyr and DPyr were highly correlated both in males and females. Pyr/DPyr ratio was significantly higher in adolescents than children, suggesting enhanced release of Pyr from extraosseous sources. In both genders, neither age nor anthropometric variables showed a linear effect on crosslinks excretion. The range of within-subject, short-term variability in urinary Pyr and DPyr was relatively high (CV: 6%–21%), indicating that single measurements of crosslinks excretion may not adequately reflect bone resorption rates in children. Pyr and DPyr levels were significantly lower in GH-deficient patients and normalized during human growth hormone (hGH) therapy. Significant correlations between growth velocity (GV) and crosslinks levels were found, but individual prediction of GV increment during hGH treatment may be inaccurate. Pyr/DPyr ratio was not related to GV. It is concluded that measurement of urinary Pyr and DPyr excretion in children may be a valuable tool to assess bone resorption rates in population-based studies. In individual patients, however, only qualitative evaluation of disease severity and response to treatment seems justified.     

Preventive effects of intermittent administration of human parathyroid hormone on steroid-induced osteopenia in rats

The purpose of this study was to determine the preventive effect of intermittent administration of human parathyroid hormone (h-PTH) on bone change in steroid-treated rats; this was done by histomorphometric and biochemical analysis. Seven-month-old female Wistar rats were divided into four groups; in-each of the four groups one subgroup was treated for 4 weeks and one for 8 weeks. The groups consisted of: untreated controls, a steroid group (receiving prednisolone), a steroid + PTH group (predniso-lone and h-PTH administered simultaneously), and a steroid + PTH vehicle group. Prednisolone (2.5 mg/kg) and h-PTH (1–34) (6.0 μg/kg) were administered six times a week during the experimental period. At necropsy, bilateral tibiae were collected: one was used for preparing undecalcified sections after Villanueva bone staining, and the other for decalcified tartrate-resistant acid phosphatase (TRAP) stained sections. Biochemical analysis showed that steroids increased urinary calcium at the 8th week; however, such bone metabolic markers as serum 1,25-(OH)₂D and urinary deoxypyridinoline did not change in any treatment group. Histomorphometrically, steroid-induced osteopenia was established at the 8th week by inhibition of both bone formation and bone resorption. The simultaneous intermittent administration of PTH plus steroid, however, increased both bone formation and bone resorption, resulting in increases in bone volume beginning at 4 weeks. These results suggest that the simultaneous intermittent administration of PTH with steroid prevents steroid-induced low-turnover osteopenia by stimulating bone turnover.