鹿茸有效成分对小鼠肝脏RNA和蛋白质合成的影响

多次给小鼠po鹿茸多胺30mg/kg,对[³H]leucine和[³H]uridine掺入肝组织蛋白和RNA有明显的促进作用,而庸茸非多胺则无此作用;当腐胺剂量为21mg/kg时,不仅促进[³H]leucine和[³H]uridiae掺入肝组织蛋白和RNA,也促进[³H]uridine掺入肝细胞核的RNA中,并增强RNA聚合酶的活性;精脒在剂量为8mg/kg时,仅对[³H]leucine掺入肝组织蛋白有促进;而精胺在1mg/kg时,没有观察到上述各种现象。此结果提示,鹿茸多胺类物质是鹿茸中刺激小鼠肝组织蛋白和RNA合成的主要活性物质,这 种刺激小鼠肝组织蛋白和RNA合成效应是由于鹿茸多胺能够显著地增强RNA聚合酶的活性。     

Effect of α-difluoromethylornithine on the polyamine levels and proliferation in two transplantable tumours

Summary The effect of inhibition of polyamine biosynthesis by-difluoromethylornithine (DFMO) on the growth of two murine transplantable tumours was studied. Female CBA mice were implanted with either the sarcoma F (SaF) or an anaplastic mammary carcinoma (CaNT), and 3% DFMO in the drinking water was provided once the tumours were established. Over a 10-day period control SaF tumours increased exponentially from 20 mm³ to over 800 mm³, whereas DFMO-treated SaF reached only 300 mm³. CaNT grew more slowly, requiring 22 days to achieve a similar volume increase, and DFMO was as effective in retarding growth as it had been in SaF. DFMO depleted tumour tissues of putrescine and spermidine, but did not reduce spermine levels. Metaphase arrest experiments with vincristine demonstrated that DFMO could substantially reduce the rates of tumour cell production, but there was no indication the DFMO accelerated the rate of cell loss from the tumours. Despite reduced rates of cell production, labelling studies with bromodeoxyuridine failed to detect differences between control and treated tumours: an increase in transit time through the S-phase was suspected. The number of nuclear organizer regions, detected by the argyrophilia of their associated proteins, was less in DFMO-treated tumours, and within a tumour the degree of silver deposition unequivocally reflected the proliferative heterogeneity. Ultrastructural studies revealed no differences between DFMO-treated and untreated tumours.     

Polyamines in Trichomonas vaginalis

Trichomonas vaginalis was grown in a modified Bushby's medium and putrescine, spermidine and spermine levels were determined in extracts from 24- and 48-h cultures and also in the culture media. All three polyamines were present in T. vaginalis extracts; the putrescine level and putrescine/spermidine ratio were much higher than those reported for other protozoa or for mammalian tissues. There were no significant differences between 24-h and 48-h amine levels per mg protein in these extracts, but amine levels per cell were higher at 24 than at 48 h. The spent culture media had a much higher putrescine content than corresponding uninoculated media and it was concluded that T. vaginalis secreted putrescine into the culture medium.     

丹酰氯柱前衍生人尿液多胺高效液相色谱(HPLC)快速测定

建立了丹酰氯柱前衍生HPLC法测定人尿中多胺含量的方法。以己二胺为内标 ,uBondapak -C18(2 5 0× 4.6mm ,10um)为固定相 ,甲醇和水为流动相 ,梯度洗脱 ,柱温 5 0℃ ,流速 1ml/min ,荧光检测器测得腐胺 (PUT)、精脒 (SPD)和精胺(SP)三者回收率为PUT 97%、SPD 98%、SP 10 3% ,回归方程线性良好 ( 均大于 0 99) ,分析时间约 9min。该法简洁 ,快速 ,灵敏度高 ,重现性好 ,可有效分析人尿及其他生物样品中的多胺含量     

Ornithine decarboxylase and polyamines in developing rat brain and heart: Effects of perinatal hypothyroidism

Hypothyroidism induced by perinatal administration of propylthiouracil (PTU) had profound effects on growth of the heart, with major organ weight deficits persisting well beyond the termination of drug treatment. These effects were preceded by disruption of the developmental patterns of cardiac ornithine decarboxylase (ODC) and the polyamines, which are thought to be intracellular modulators of cellular maturation. Activity of cardiac ODC was depressed in the PTU-treated group and putrescine and spermidine levels were markedly subnormal. PTU administration also affected brain growth, but much less so than in the heart. The disruption of the brain ODC/polyamine system was also less pronounced, with relatively small degrees of spermidine depletion and a slight elevation of ODC. For both tissues, the biochemical effects of perinatal hypothyroidism were opposite to those found previously for administration of exogenous thyroid hormones. These results support the views that:

1. (1) endogenous thyroid hormones contribute to the maintenance of normal developmental patterns of ODC and the polyamines, and

2. (2) the ODC/polyamine system participates in events modulating subsequent tissue growth.

The additive effect ofα-difluoromethylornithine (DFMO) and radiation therapy on a rat glioma model

Summary The effects of -difluoromethylornithine (DFMO), radiation and the therapy of their combination were investigated in rats bearing G-XII glioma. DFMO treatment as well as radiation therapy prolonged the survival period when compared to the results in non-treated control rats. The combination therapy showed a greater effect on the survival rate than the single therapies, the effect being additive. The concentration of putrescine, spermidine, andN ¹-acetylspermidine in tumor tissues was lowered by DFMO, while that of spermine was slightly elevated. Radiation decreased the concentration of all the polyamines, putrescine, spermidine, spermine andN ¹-acetylspermidine. The concomitant treatment with DFMO and radiation further decreased the concentrations of putrescine andN ¹-acetylspermidine in tumor tissues. The survival period of glioma-bearing rats is inversely correlated with the tissue levels of putrescine plusN ¹-acetylspermidine.Abbreviations DFMO -difluoromethylornithine - BrdUrd bromodeoxyuridine     

Effect of β-endorphin on cell growth and cell death in human peripheral blood lymphocytes

Beta-endorphin (β-end) was investigated for its ability to influence sequential metabolic events that accompany the movements of T-lymphocytes into the cell cycle. When cultured lymphocytes are exposed to this endogenous opioid peptide an increase in polyamine transport across cell membrane is observed. This membrane modification is an early cell cycle event, whose enhancement leads to the intracellular polyamine accumulation. It is shown that β-end is able to enhance spermidine transport and that the exposition of cells to this peptide is perceived as an apoptotic signal. The possible relationship between induction of apoptotic death and enhancement of polyamine uptake is discussed.     

DFMO通过Fas/FasL通路诱导人肺癌细胞凋亡的研究

背景与目的:Fas/FasL系统是细胞凋亡的重要通路。为了解Fas/FasL系统在肿瘤多胺生物合成抑制导致恶性表型逆转中的作用,本研究拟探讨多胺生物合成抑制剂α-二氟甲基鸟氨酸(α-difluoromethylornithine,DFMO)对人肺癌A549细胞生长、凋亡的影响及其与人肺癌相关抗原、rasP21蛋白及Fas/FasL表达的相关性。方法:用MTT法观察细胞生长,流式细胞仪分析细胞周期,DNAladder电泳法观察细胞凋亡,SP免疫组化法及RT-PCR法检测细胞蛋白及基因表达。结果:DFMO可抑制A549细胞生长并诱导凋亡,使G1期细胞增多(61.0±2.08)%,S期细胞减少(21.2±0.88)%,出现DNAladder;同时下调A549细胞人肺癌相关抗原及rasP21蛋白表达,上调Fas基因mRNA及蛋白表达。结论:DFMO通过Fas/FasL通路诱导肺癌A549细胞的凋亡,并可能与人肺癌相关抗原及rasP21蛋白表达调控有关。     

Role of polyamines in intestinal adaptation in the rat

The cellular mechanisms controlling adaptive intestinal mucosal hypo- and hyperplasia are poorly understood but changes in tissue polyamine levels and in the activity of the key enzymes controlling their synthesis (ornithine decarboxylase: ODC) and degradation (diamine oxidase: DAO) have been implicated. Therefore, in two models of adaptive mucosal hyperplasia (pancreatico-biliary diversion, PBD, achieved by surgically transposing the jejunum to lie between pylorus and ampulla of Vater, and 90% small bowel resection, SBR-both studied 8 weeks after surgery) and in one model of hypoplasia (8 days total parenteral nutrition) we measured indices of mucosal mass (wet weight, protein and DNA per 10-cm intestine), the growth-associated polyamines (putrescine, spermidine and spermine per 10-cm intestine and per mg DNA) and DAO activity in the duodenum, five 10-cm segments of jejunum, five 10-cm segments of ileum and in the colon, and compared the results with those found in transected or unoperated controls. The results for the indices of mucosal mass confirmed that TPN led to a modest degree of small bowel mucosal hypoplasia whilst PBD, and particularly 90% SBR, stimulated marked adaptive hyperplasia. There were corresponding changes in the amounts of putrescine and spermidine (but not of spermine)-not only when the results were expressed per unit length but also when calculated per mg mucosal DNA and in the ratio of spermidine:spermine. There was an increasing proximal-to-distal gradient in mucosal DAO per unit length intestine in all experimental groups but when the results were expressed per mg DNA, the ileal DAO levels were significantly reduced in the PBD and resection groups, when compared with the controls. These data support the hypothesis that polyamines play a major, and perhaps a controlling, role in regulating adaptive intestinal mucosal growth.     

CLONING AND EXPRESSION OF A GENE ASSOCIATED WITH HL60 CELL APOPTOSISINDUCED BY INHIBITION OF POLYAMINE BIOSYNTHESIS

Objective: To clone the gene associated with apoptosis induced by an inhibitor of polyamine biosynthesis, α-difluoromethylornithine (DFMO). Methods: The differential subtraction screening was used for gene cloning from cDNA library of HL₆₀ cells treated by DFMO. Northern blot, morphological observation, FCM assays and ladder map of DNA electrophoresis were performed. Results: The transfecting gene expression and activity of inducing apoptosis in the cells transfected from recombinant plasmid containing the cloned fragment df4 was proved. Conclusion: It is suggest that df4 gene cloned in the study could be a gene regulating apoptosis of HL₆₀ cells.