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本文证明抗孕53号有降低妊娠大鼠血浆孕酮水平的作用,血浆孕酮水平的下降发生在胎仔死亡前。用去卵巢大鼠,以孕激素维持妊娠,抗孕53号及SIPPR-113的抗孕激素的维持妊娠作用与它们的雌激素活性有密切关系,雌激素活性是这类化合物的抗生育作用的主要但不是唯一因素。 相似文献
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卵巢孕酮对多种动物的早期妊娠起着必不可少的作用,切断孕酮的来源将终止其妊娠。通过诱导功能性的溶黄体作用或用抗体使循环中的孕酮失效都可能中断妊娠。阻断孕酮功能的目的,理论上可以通过阻断它结合于其子宫受体来达到。曾有报道,一种药物R-2323,在人体其作用是可疑的,月经过期后给药它似乎不起流产作用,月经中期给药,它作为假想的孕酮拮抗剂而起抗着床作用,也可能由于它抑制垂体促性腺激素的分泌而起抗排卵作用。本文介绍了寻找孕酮竞争性拮抗剂的方案。如图所示,第一个程序受体结合能力并不是结论性的,因这种结合既表征激动剂又表征拮抗剂。因而有一定结合亲和力的化合物要继以孕激素活性和抗孕激素活性的生物学试验,即对家兔子宫内膜转化的抑制或刺激作用,对去势大鼠孕酮维持妊娠的抑制作用,对大鼠和金地鼠着床后的妊娠终止作用。 相似文献
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7α-和7β-甲基-10β,17β-二乙酰氧基-△~4-雌甾烯-3酮(简称7α-和7β-甲-乙氧雌酮)对小鼠抗早孕ED_(50)分别为1.6和5.5 mg/kg。7α-甲-乙氧雌酮在大鼠也有抗早孕作用并使血浆孕酮浓度降低,应用10 μg/ml浓度能抑制离体妊娠大鼠卵巢孕酮合成。7α-和7β-甲-乙氧雌酮与兔子宫胞浆雌二醇受体的相对结合亲和力(RBA)分别为10.8和1.5,与孕酮受体的RBA均<1.7α-和7β-甲-乙氧雌酮都有较弱的雌激素和抗雌激素活性。 相似文献
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天花粉对大鼠有抗早孕作用,使妊娠大鼠血浆孕酮浓度,子宫中孕酮和孕酮受体的含量下降,子宫中的PGF_(2α)含量增高,同时增敏子宫对15-Me-PGR_(2α)和催产素的反应性,消炎痛能抑制离体妊娠子宫自发收缩活动,但并不抑制天花粉增敏子宫对15-Me-PGF_(2α)和催产素反应性的作用,实验结果提示天花粉促进子宫PGF_(2α)的含量增加和增敏子宫对催产物质的反应性是它增加妊娠子宫自发收缩活动的重要机制,而天花粉的上述作用又可能与它使子宫中孕酮和孕酮受体下降有关 相似文献
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天花粉对大鼠有抗早孕作用,使妊娠大鼠血浆孕酮浓度,子宫中孕酮和孕酮受体的含量下降,子宫中的PGF2α含量增高,同时增敏子宫对15-Me-PGR2α和催产素的反应性,消炎痛能抑制离体妊娠子宫自发收缩活动,但并不抑制天花粉增敏子宫对15-Me-PGF2α和催产素反应性的作用,实验结果提示天花粉促进子宫PGF2α的含量增加和增敏子宫对催产物质的反应性是它增加妊娠子宫自发收缩活动的重要机制,而天花粉的上述作用又可能与它使子宫中孕酮和孕酮受体下降有关。 相似文献
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酪氨酸单用及合并RU486对小鼠生殖功能的影响及作用机理 总被引:1,自引:0,他引:1
用小鼠抗早孕实验及体外大鼠黄体细胞培养的方法,研究酪氨酸单用及酪氨酸与已知抗生育药RU486合并用药对小鼠早期妊娠的影响及作用机制。结果表明,酪氨酸与RU486合用有协同抗早孕作用。进一步的机理研究发现,酪氨酸170mg·kg-1·5d可使早孕小鼠血清孕酮水平显著降低;酪氨酸50μg·mL-1与(+)PG05合用;对抑制大鼠黄体细胞孕酮的基础分泌有协同作用,并能显著抑制hCG诱导的大鼠黄体细胞孕酮的分泌。结果提示:降低孕酮分泌可能是酪氨酸抗生育作用的途径之一。 相似文献
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米非司酮在治疗子宫内膜异位症中的临床应用 总被引:1,自引:0,他引:1
米非司酮(Mifepristone),国产商品名为息隐、含珠停.作为受体水平抗孕激素药,具有终止早孕、抗着床、诱导月经及促进宫颈成熟等作用,与孕酮竞争受体而达到拈抗孕酮的作用,与糖皮质激素受体亦有一定结合力。米非司酮能明显增高妊娠子宫对前列腺素的敏感性。 相似文献
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孕酮对吗啡精神依赖大鼠海马和纹状体中阿片受体水平的影响 总被引:2,自引:2,他引:0
目的观察孕酮对于吗啡所致奖赏效应及海马和纹状体μ受体水平的影响。方法32只SD大鼠随机分为空白对照组、吗啡组、孕酮组和孕酮加吗啡组,并建立吗啡条件性位置偏爱(CPP)模型,采用免疫组化法测定大鼠海马和纹状体中μ受体的水平。结果与空白对照组比较,5 mg.kg-1吗啡可诱导大鼠产生稳定的CPP效应(P<0.01),15 mg.kg-1孕酮本身不产生CPP效应,但能抑制吗啡的CPP效应。与空白对照组比较,吗啡CPP形成时,海马和纹状体中μ受体的数量降低(均为P<0.01)。与吗啡组比较,合用15 mg.kg-1孕酮可使纹状体中μ受体的数量升高(P<0.05),而在海马中未见变化。结论孕酮可以有效抑制吗啡CPP效应,其机制可能与其逆转吗啡诱导的纹状体中μ受体水平的变化有关。 相似文献
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Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.
Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.相似文献
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《Critical reviews in toxicology》2013,43(5-6):327-369
AbstractThe uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors. 相似文献
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Petrikovics I McGuinn WD Sylvester D Yuzapavik P Jiang J Way JL Papahadjopoulos D Hong K Yin R Cheng TC DeFrank JJ 《Drug delivery》2000,7(2):83-89
This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine. 相似文献
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《Expert opinion on investigational drugs》2013,22(1):79-86
Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation. 相似文献
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Chang Min Kim Kun Ho Son Sung Hwan Kim Hyun Pyo Kim 《Archives of pharmacal research》1991,14(4):305-310
In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins
from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins. 相似文献
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