Role of growth hormone in regulation of polynucleotide-phosphorylase activity in rat liver

Hypophysectomy in rats is followed by a significant increase in polynucleotide-phosphorylase (PNPase) activity in ribosomal fractions of the liver. Injection of growth hormone into hypophysectomized animals leads to inhibition of PNPase activity. Within the dose range from 5 to 100 g the dose—effect curve is linear. The action of growth hormone is most marked 18h after a single injection.Laboratory of Enzymology, Academy of Medical Sciences of the USSR, and Laboratory of Biological Standardization of Hormones, Institute of Experimental Endocrinology and Hormone Chemistry, Academy of Medical Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 2, pp. 162–163, February, 1980.     

Effect of thyrotrophin releasing hormone on secretion of thyrothrophic hormone and prolactin in a monolayer culture of rat adenohypophysis

Cells of the adenophypophysis in a primary 5–8-day monolayer culture react to addition of thyrotrophin releasing hormone (TRH) by rapid dose-dependent liberation of thyrotrophic hormone (TSH) and prolactin into the culture medium. This effect is independent of the content of serum in the nutrient medium. The thyroid hormone thyroxin blocks the stimulating action of TRH on the secretion of TSH, but not of prolactin. The blocking effect of thyroxin is evidently manifested not on cell membranes, but in the cytoplasm distally to the effect of cyclic AMP, along the pathway of transmission of the hormonal signal.Laboratory of Biological Standardization of Hormones, Institute of Experimental Endocrinology and Hormone Chemistry, Academy of Medical Sciences of the USSR, Moscow. Department of Morphology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Yudaev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 2, pp. 215–217, February, 1978.     

Effect of some regulators on rat adenohypophyseal cell function in primary monolayer culture

Some features of secretion of labeled somatotrophic hormone (STH) and prolactin in a 5-day monolayer culture of rat adenohypophyses were studied. Hormones were isolated from the culture medium by electrophoresis in polyacrylamide gel. Sodium-dibutyryl cyclic AMP and theophylline stimulated STH and prolactin secretion. Thyrotrophin releasing hormone (TRH) increased the rate of incorporation of L-leucine-¹⁴C into the cell proteins, stimulated prolactin secretion, but did not affect STH liberation. Somatostatin completely inhibited theophylline-induced STH secretion but did not affect prolactin secretion. The characteristics of formation of the labeled STH and prolactin pool in the cells and of the secretion of these hormones into the culture medium are discussed.Laboratory of Biological Standardization of Hormones, Institute of Experimental Endocrinology and Hormone Chemistry, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Yudaev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 10, pp. 491–495, October, 1978.     

Preparation of primary monolayer cultures of adult rat hepatocytes

Summary We describe in detail the technique of hepatocyte isolation and establishment of primary cell cultures of adult rat hepatocytes. These cultures contain hormonally responsive hepatocytes that retain many adult characteristics under completely serum-free conditions. The cells retain a normal morphology and do not exhibit fetal characteristics during a 4 d culture period.     

Influence of cell culture configuration on the post-cryopreservation viability of primary rat hepatocytes

Cryopreservation has been identified as a necessary barrier to overcome in the production of tissue engineered products for clinical application. Liver engineering and bioartificial liver assisting devices are on the forefront of tissue engineering research due to its high demand and clinical potential. In this study we propose that the cryopreservation of primary mammalian hepatocytes yields better results when these cells are in a tissue-like culture configuration since cell attachment is essential for cell survival in this cell type. We used two different tissue-engineered culture configurations: monolayers and spheroid culture; and two different concepts of cryopreservation, namely vitrification and freezing. Cell suspensions were also cryopreserved using both approaches and results were compared to the engineered cultures. Both engineered configurations and suspension were cryopreserved using both conventional freezing (cooling at 1 °C/minute using 10% DMSO in foetal calf serum) and vitrification (using 40% ethylene glycol 0.6 m sucrose supplemented with 9% Ficoll). These two approaches differ on the degree of mechanical stress they inflict on the material to be cryopreserved. The maintenance of cell-to-cell and the integrity of the actin cytoskeleton were assessed using scanning electron microscopy and immunohistochemistry respectively. Results showed that while there was no significant difference between the degree of integrity shown between vitrified and control engineered cultures, the same did not happen to the frozen engineered constructs. The disruption of the cytoskeletal structure correlated with increased levels of apoptotic markers. With cryopreserved suspensions there was evidence of disruption of the cytoskeletal structure. This study concluded that cell-to-cell contact is beneficial in the maintenance of viability post-cryopreservation and that the vitrification approach was far superior to those of conventional freezing when applied to 2D and 3D hepatocyte based engineered cultures.     

Influence of adrenocorticotropic hormone on the growth of isolated neurons in culture

The present study reports the influence of adrenocorticotropic hormone (ACTH) on the development of cultured neurons from chick embryo cerebral hemispheres. Cultures were initiated in serum-supplemented medium and then transferred to serum-free hormonally-defined medium containing various concentrations of ACTH1--24. The effects of ACTH on the light microscopic features, metabolic activity and permeation properties were examined. The results demonstrate that ACTH exerts a trophic action on the neurons.     

Improved sensitivity of the unscheduled DNA synthesis assay in primary rat hepatocytes following culture in serum-free defined media

The unscheduled DNA synthesis (UDS) assay has been used extensively for the in vitro detection of DNA damage caused by compound exposure. However, the in vitro UDS assay has been insensitive for the detection of certain chemicals, particularly nitroaromatic compounds, that are positive in bacterial mutation assays. Recently, studies have been reported which describe alterations in the he-patocyte membrane following collagenase perfusion. Independently, a method for serum-free tissue culture has been developed which results in the up-regulation of cell surface receptors and which may restore membrane functions. Fourteen compounds, including seven nitroaromatics, were evaluated in the in vitro UDS assay employing a serum-free procedure. Five compounds that were previously reported positive in the standard in vitro UDS assay were also found positive using the serum-free method. In addition, five of the nitroaromatic compounds produced positive results with the serum-free method. 1-Methyl-3-nitro-1-nitrosoguanidine and 2-acetylaminofluorene, routinely used as positive controls in the UDS assay, showed greater activity in the serum-free assay. These results suggest that the use of serum-free media improves the sensitivity of the in vitro UDS assay and that the serum-free procedure potentially offers an effective alternative to the more labor intensive and more costly in vivo UDS assay. © 1995 Wiley-Liss, Inc.     

聚乙二醇化重组人生长激素对离体豚鼠乳头肌细胞动作电位的影响

目的 探讨聚乙二醇化重组人生长激素(PEG-rhGH)对离体豚鼠乳头肌细胞动作电位的影响,并以重组人生长激素(rhGH)为阳性对照物比较二者的体外生物活性.方法 健康雄性DHP豚鼠12只,随机分为2组,PEG-rhGH干预组和rhGH干预组,每组6只.采用累计给药法和给药前后自身对照方法,分别观察不同质量浓度(1、5、...     

Effect of complexes of apolipoprotein A-I with tetrahydrocortisol and pregnenolone on protein biosynthesis in rat hepatocytes culture

Complexes of apolipoprotein A-I with tetrahydrocortisol and pregnenolone exhibit high biological activity and increase the rate of protein biosynthesis in the culture of rat hepatocytes. An important role in this process is played by reduced Δ⁴-3-keto group in the A-ring of steroid hormones. A complex of apolipoprotein A-I and pregnenolone modulated the rate of protein biosynthesis in liver cells. Hence, the observed changes are not organ-specific for this steroid. Our results suggest that this mechanism of regulation play an important role in intracellular regeneration and proliferation. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 9, pp. 264–266, September, 2007     

实验性肝硬化肝细胞生长激素受体的表达与动态变化

目的:探讨实验性肝硬化细胞生长激素受体的表达变化。方法:采用硫代乙酰胺腹腔注射复制大鼠肝硬化模型,采用放射配体法、RT-PCR、图像分析检测不同阶段肝硬化肝组织和肝硬化肝细胞中生长激素受体及其mRNA的表达水平,并分别与正常肝组织和正常肝细胞比较。结果:大鼠肝硬化肝组织表达生长激素受体,其表达数量明显少于正常肝组织,并且随着肝硬化的进展、肝组织胶原纤维相对含量的增加而进一步减少;大鼠肝硬化肝细胞生长激素受体的位点数量明显少于正常肝细胞,大鼠肝硬化肝组织生长激素受体mRNA的表达量也明显少于正常肝组织。结论:大鼠肝硬化肝细胞表达生长激素受体,其表达水平降低;肝硬化越严重,该表达减少越明显。大鼠肝硬化肝组织生长激素受体表达下调的机制可能是肝硬化肝组织生长激素受体mRNA的表达明显减少。     

Taurocholate depolarizes rat hepatocytes in primary culture by increasing cell membrane Na+ conductance

Rat hepatocytes in primary culture were impaled with conventional microelectrodes. Addition of 5–100 mol/l taurocholate led to a slowly developing depolarization that was maximal at 50 mol/l (10.5±1.5 mV, n=15) and not reversible. The effect was Na⁺ dependent and decreased in cells preincubated with 1 mol/l taurocholate. Increasing external K⁺ tenfold depolarized the cells by 12.3±2.3 mV under control conditions and by 6.3±1.2 mV with 50 mol/l taurocholate present (n=7). Depolarization by 1 mmol/l Ba²⁺ was 7.6±0.8 mV and 6.0±0.7 mV (n=9) before and after addition of taurocholate, respectively. Cable analysis and Na⁺ substitution experiments reveal that this apparent decrease in K⁺ conductance reflects an actual increase in Na⁺ conductance: in the presence of taurocholate, specific cell membrane resistance decreased from 2.8 to 2.3 k · cm² · Na⁺ substitution by 95% depolarized cell membranes by 8.9±2.9 mV (n=9), probably due to indirect effects on K⁺ conductance via changes in cell pH. With taurocholate present, the same manoeuvre changed membrane voltages by –0.8±2.6 mV. When Na⁺ concentration was restored to 100% from solutions containing 5% Na⁺, cells hyperpolarized by 3.5±3.6 mV (n=7) under control conditions and depolarized by 4.4±2.9 mV in the presence of taurocholate, respectively. In Cl^– substitution experiments, there was no evidence for changes in Cl^– conductance by taurocholate. These results show that taurocholate-induced membrane depolarization is due to an increase in Na⁺ conductance probably via uptake of the bile acid.     

肝细胞培养过程中酸碱度和溶解氧的关联控制

目的在生物型人工肝支持系统(BAL)中,设计一种能够精确控制溶解氧(D0)与酸碱度(pH)的控制方案.方法根据肝细胞培养过程中所需要的物料衡算,采用比例积分(PI)算法结合开关量控制、预测控制等方案,通过工控机构建关联控制系统,使得D0与pH的值相互关联.结果DO控制范围0%～200%,精度达到±5%;pH控制范围6～8,精度达到±0.05.结论经实验证实,本控制方案工作稳定,无静态误差,解决了培养过程中DO与pH相互影响的问题,可用于BAL中对肝细胞培养环境的控制.     

重组人生长激素对内毒素血症大鼠的治疗作用

目的 :观察重组人生长激素 (rhGH)对大鼠内毒素血症的治疗效果。方法 :76只SD大鼠随机分为正常对照组、内毒素血症组 (仅腹腔注射鸵鸟株大肠杆菌 (1 5ml/kg ,1× 1 0 10 cfu/L)及治疗组 (腹腔注射鸵鸟株大肠杆菌后行rhGH肌肉注射 (2 2 5IU/kg/d)。内毒素血症组及治疗组又依观察时点再分为 1天、3天两个亚组。采用放射免疫分析方法测定血浆肿瘤坏死因子 α(TNF α)浓度并观测大鼠血压的变化。结果 :与正常对照组相比 ,无论是内毒素血症组还是治疗组 ,1天时其大鼠血浆TNF α浓度均明显升高 (P <0 .0 5 ) ;虽然两组大鼠血压都降低 (P <0 .0 5 ) ,但治疗组大鼠血压降低幅度明显小于内毒素血症组 (P <0 .0 0 1 )。 3天时 ,内毒素血症组大鼠血浆TNF α浓度降至正常对照水平 ,而治疗组大鼠血浆TNF α浓度却明显低于正常对照组 (P <0 .0 0 1 )及内毒素血症组 3天水平 (P <0 .0 5 )。结论 :rhGH能明显减轻内毒素血症大鼠血压的下降 ,对内毒素血症大鼠具有较理想的治疗效果 ;rhGH减轻血压下降的机制可能与其能抑制TNF的释放等有关     

Andrology: Effect of growth hormone administration on circulating levels of luteinizing hormone, follicle stimulating hormone and testosterone in normal healthy men

A new area of growth hormone (GH) therapy in adults is the treatmentof infertility. The aim of this study was to evaluate the effectsof pharmacological GH administration on the secretion of pituitaryand gonadal hormones in normal men. Eight healthy men, 23–32years of age (mean 28.1 years), with a normal body mass indexwere studied in a double-blind, placebo-controlled crossoverdesign. All participants had a normal semen analysis beforeentering the study. Each participant was treated with placeboand GH (12/IU/day, Norditropin; Novo Nordisk, Denmark) duringtwo different 14-day periods, separated by a 6 week washoutperiod. Administration of GH for 14 days resulted in a significantincrease in serum insulin-like growth factor I (IGF-I; P <0.01) but no changes occurred in IGF-I values during placebotreatment. The concentrations of follicle stimulating hormoneand luteinizing hormone displayed no change during the two periodsand did not differ between the GH treatment period and the placeboperiod. The concentration of testosterone was unchanged duringthe placebo/GH periods and there was no difference between theGH treatment period and the placebo period. We conclude thatGH treatment for 14 days in normal healthy men does not affectgonadotrophin or testosterone patterns.