Vuppugalla Ragini, Shah Rakhi B, Chimalakonda Anjaneya P, Fisher Charles W, Mehvar Reza
School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas 79106, USA.
Pharm Res. 2003 Jan;20(1):81-8. doi: 10.1023/a:1022202926073.
We recently showed that the perfusion of isolated rat livers with perfusates containing bovine serum albumin (BSA) would significantly stimulate the release of tumor necrosis factor (TNF)-alpha. Here, we hypothesize that BSA-induced increase in the release of TNF-alpha, and possibly other cytokines, would affect cytochrome P450 (CYP)-mediated drug metabolism.
Rat livers were perfused ex vivo for 1, 2, or 3 h with a physiologic buffer containing or lacking 1% BSA (n = 4-5/group). At the end of perfusion, liver microsomes were prepared and analyzed for their total CYP, CYP2E1, CYP3A2, and CYP2C11 protein contents and the activities of cytochrome c reductase, CYP2E1, CYP3A2, CYP2C11, CYP2E1, CYP2D1, CYP1A1, and CYP2B1/2. In addition, the concentrations of various cytokines and nitric oxide were quantified in the outlet perfusate.
In the absence of BSA, the perfusate levels of all measured cytokines and nitric oxide were low. However, when the perfusate contained BSA, the levels of TNF-alpha, interleukin-6, and nitric oxide increased significantly (p < 0.005). Perfusion of the livers for 3 h with the BSA-containing perfusate resulted in significant (p < 0.05) decreases in the total CYP (41%), CYP2E1 (59%), CYP3A2 (68%), and CYP2C11 (50%) protein contents and activities of cytochrome c reductase (31%), CYP2E1 (66%), CYP3A2 (54%), and CYP2G11 (51%). In contrast, perfusion of livers for 1 or 2 h with the BSA perfusate did not have any significant effect on CYP-mediated metabolism. The CYP1A2, CYP2D1, and CYP2B1/2 activities were not affected by BSA, regardless of perfusion time.
Addition of BSA to perfusates, which is a routine practice in isolated rat liver studies, can reduce CYP-mediated drug metabolism by a mechanism independent of protein-binding effect.
我们最近发现，用含有牛血清白蛋白（BSA）的灌注液灌注离体大鼠肝脏会显著刺激肿瘤坏死因子（TNF）-α的释放。在此，我们假设BSA诱导的TNF-α以及可能其他细胞因子释放增加会影响细胞色素P450（CYP）介导的药物代谢。
将大鼠肝脏在含有或不含1% BSA的生理缓冲液中离体灌注1、2或3小时（每组n = 4 - 5）。灌注结束时，制备肝微粒体并分析其总CYP、CYP2E1、CYP3A2和CYP2C11蛋白含量以及细胞色素c还原酶、CYP2E1、CYP3A2、CYP2C11、CYP2E1、CYP2D1、CYP1A1和CYP2B1/2的活性。此外，对流出灌注液中的各种细胞因子和一氧化氮浓度进行定量。
在没有BSA的情况下，所有测量的细胞因子和一氧化氮的灌注液水平都很低。然而，当灌注液含有BSA时，TNF-α、白细胞介素-6和一氧化氮的水平显著升高（p < 0.005）。用含BSA的灌注液灌注肝脏3小时导致总CYP（41%）、CYP2E1（59%）、CYP3A2（68%）和CYP2C11（50%）蛋白含量以及细胞色素c还原酶（31%）、CYP2E1（66%）、CYP3A2（54%）和CYP2G11（51%）的活性显著降低（p < 0.05）。相比之下，用含BSA的灌注液灌注肝脏1或2小时对CYP介导的代谢没有任何显著影响。无论灌注时间如何，CYP1A2、CYP2D1和CYP2B1/2的活性均不受BSA影响。
在灌注液中添加BSA（这是离体大鼠肝脏研究中的常规做法）可通过一种独立于蛋白结合效应的机制降低CYP介导的药物代谢。
