Characterization of a specific, high affinity [3H]arginine8 vasopressin-binding site on liver microsomes from different strains of rat and the role of magnesium.
Characterization of a specific, high affinity [3H]arginine8 vasopressin-binding site on liver microsomes from different strains of rat and the role of magnesium.
复制标题
不同品系大鼠肝微粒体上特异性高亲和力 [3H]精氨酸8 加压素结合位点的表征以及镁的作用。
作者：
V. Gopalakrishnan;C. Triggle;P. Sulakhe;J. Mcneill
在大鼠肝脏的质膜富集微粒体部分中发现了一类高亲和力、低容量的[3H]精氨酸-抗利尿素（AVP）特异性结合位点。特异性结合是饱和的，与蛋白质浓度成线性关系，可逆的，占总结合的40-65%。在25℃条件下，结合在30分钟后达到平台期，而在4℃条件下，达到平衡的速度较慢，结合水平降低。在实验培养基中，镁（Mg2+）的存在增强了特异性结合的亲和力，而钙和高水平的钠和钾则降低了结合。在Mg2+ (5 mM)存在下的Scatchard分析显示，平均+/- SE平衡解离常数（Kd）为0.29 +/- 0.08 nM，最大位点密度（Bmax）为150.4 +/- 25.0 fmol/mg；未添加Mg2+时，Kd为1.93 +/- 0.33 nM， Bmax为113.4 +/- 40.0 fmol/mg。自发性高血压大鼠、Wistar-Kyoto大鼠、Long-Evans大鼠和Brattleboro大鼠的膜组分Kd和Bmax均无显著差异。自发性高血压大鼠、Wistar-Kyoto大鼠和Long-Evans大鼠的血浆AVP水平相似，但DI大鼠的血浆中未检测到AVP。未标记AVP及其相关肽对特异性[3H]AVP结合的竞争性抑制显示Ki值如下：AVP， 0.19 nM；LVP, 1.7 nM；催产素，41.4 nM；去氨基AVP， 0.38 nM；[1-（β -巯基- β， β -环五亚甲基丙酸）4-Val,8-D-Arg] VP2-（o-甲基）酪氨酸]AVP， 1.8 nM；去甘氨酸酰胺AVP， 2.2微米。AVP的神经肽代谢物[[pGlu4，Cyt6] AVP-(4-9)]、血管紧张素II和其他不相关肽没有取代[3H]AVP，这表明AVP及其相关生物活性肽对该结合位点具有特异性。此外，这些不同肽取代[3H]AVP结合的效力的等级顺序与它们在肝脏中报道的糖原溶解活性和/或它们在血管平滑肌中的激动或拮抗效力相似。最后，Mg2+诱导的[3H]AVP对该肝脏结合位点的亲和力增加与Mg2+对血管平滑肌对AVP收缩反应的影响相似（即亲和力增加）。结果与大鼠肝微粒体高亲和受体位点为V1型的解释一致。
A single class of high affinity, low capacity, specific binding sites for [3H]arginine8 vasopressin (AVP) has been characterized in a plasma membrane-enriched microsomal fraction of the rat liver. Specific binding was saturable, linear with protein concentration, reversible, and 40-65% of the total binding. Binding at 25 C achieved a plateau after 30 min of incubation, whereas at 4 C, equilibrium was reached more slowly, and the level of binding was reduced. The presence of magnesium (Mg2+) in the assay medium enhanced the affinity of specific binding, while calcium and higher levels of sodium and potassium decreased binding. Scatchard analysis of binding in the presence of Mg2+ (5 mM) revealed an apparent mean +/- SE equilibrium dissociation constant (Kd) of 0.29 +/- 0.08 nM, with a maximal site density (Bmax) of 150.4 +/- 25.0 fmol/mg; in contrast, the Kd was 1.93 +/- 0.33 nM and the Bmax was 113.4 +/- 40.0 fmol/mg in the absence of Mg2+. No significant differences in Kd and Bmax were observed among membrane fractions derived from spontaneously hypertensive rats, Wistar-Kyoto rats, Long-Evans rats, and Brattleboro rats. Plasma levels of AVP were similar in spontaneously hypertensive, Wistar-Kyoto, and Long-Evans rats, but AVP was not detectable in the plasma from DI rats. Competitive inhibition of specific [3H]AVP binding by unlabeled AVP and related peptides showed the following Ki values: AVP, 0.19 nM; LVP, 1.7 nM; oxytocin, 41.4 nM; desamino AVP, 0.38 nM; [1-(beta-mercapto-beta, beta-cyclopentamethylene propionic acid) 4-Val,8-D-Arg] VP2-(O-methyl)tyrosine]AVP, 1.8 nM; desglycinamide AVP, 2.2 microM. The neuropeptide metabolite of AVP [[pGlu4,Cyt6] AVP-(4-9)], angiotensin II, and other unrelated peptides did not displace [3H]AVP, demonstrating the specificity of AVP and its related biologically active peptides for this binding site. Moreover, the rank order of potency for displacement of [3H]AVP binding by these various peptides parallels their reported glycogenolytic activity in liver and/or their agonistic or antagonistic potency in vascular smooth muscle. Finally, the Mg2+-induced increase in the affinity of [3H]AVP for this liver binding site is similar to the reported effect of Mg2+ on the contractile responses of vascular smooth muscle to AVP (i.e. increased affinity). The results are consistent with the interpretation that the high affinity receptor site characterized in rat liver microsomes is of the V1 type.
抑制肝 α1-肾上腺素能效应并与佛波醇肉豆蔻酸酯乙酸酯结合。
DOI：
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发表时间：
1985
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Lynch,CJ;Charest,R;Bocckino,SB;Exton,JH;Blackmore,PF
通讯作者：
Blackmore,PF
肝细胞中加压素和肾上腺素诱导的磷脂酰肌醇分解是钙依赖性的。
DOI：
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发表时间：
1982
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Prpić,V;Blackmore,PF;Exton,JH
通讯作者：
Exton,JH
加压素和去氧肾上腺素对肝细胞质膜 Ca2-Mg2-ATPase 活性的调节。
影响因子：
4.8
作者：
Lin,SH;Wallace,MA;Fain,JN
通讯作者：
Fain,JN