Barnea A, Hartter D E, Cho G, Bhasker K R, Katz B M, Edwards M D
Department of Obstetrics and Gynecology, University of Texas, Dallas.
J Inorg Biochem. 1990 Oct;40(2):103-10. doi: 10.1016/0162-0134(90)80043-w.
We have previously demonstrated that hypothalmic slices obtained from adult male rats accumulate 67Cu by two ligand-dependent, saturable processes: a high and low affinity process. To further establish the generality of these uptake processes, we defined the ligand requirements and the saturation kinetics of 67Cu uptake by tissue slices obtained from the newborn hypothalamus (HT); adult male hypothalamus, hippocampus, cortex, median eminence, and caudate nucleus; hypothalamus and hippocampus of castrated (14 days) males and of pregnant (19 days) and ovariectomized (14 days) females. It was found that ionic 67Cu2+ was poorly taken up by newborn HT and adult caudate, complexation with His enhanced 67Cu uptake 3-4-fold, and complexation with albumin inhibited 67Cu uptake. These ligand requirements are identical to those we have previously shown for the adult HT. When 67Cu uptake was evaluated under conditions optimal for the high or the low affinity process, for each process the dose response curves generated from these various tissues were very similar. In addition, we assessed the uptake of both components of the CuHis2 complex by incubating tissues with 67Cu3 H-His2 and found that the tissue ratio of 67Cu:3H was a sigmoidal function of the concentration of the Cu complex such that at greater than 5 microM, the ratio was about 3-fold greater than the medium ratio; indicating preferential uptake of 67Cu relative to 3H-His. The changes in isotope ratios were observed in newborn HT and adult HT, as well as caudate. These similarities in the ligand requirements and saturation kinetics of 67Cu uptake establish the generality of these two processes of in vitro uptake of copper in the rat brain.
我们之前已经证明，从成年雄性大鼠获得的下丘脑切片通过两种配体依赖性、可饱和过程积累67Cu：一种是高亲和力过程，另一种是低亲和力过程。为了进一步确定这些摄取过程的普遍性，我们确定了从新生下丘脑（HT）；成年雄性下丘脑、海马体、皮质、正中隆起和尾状核；去势（14天）雄性以及怀孕（19天）和去卵巢（14天）雌性的下丘脑和海马体获得的组织切片对67Cu摄取的配体需求和饱和动力学。结果发现，离子67Cu2+在新生HT和成年尾状核中的摄取较差，与组氨酸络合可使67Cu摄取增加3 - 4倍，而与白蛋白络合则抑制67Cu摄取。这些配体需求与我们之前对成年HT所显示的需求相同。当在高亲和力或低亲和力过程的最佳条件下评估67Cu摄取时，对于每个过程，从这些不同组织产生的剂量反应曲线非常相似。此外，我们通过用67Cu3H - His2孵育组织来评估CuHis2络合物的两种成分的摄取，发现67Cu:3H的组织比率是铜络合物浓度的S形函数，使得在大于5 microM时，该比率比培养基比率大约高3倍；表明相对于3H - His，67Cu有优先摄取。在新生HT和成年HT以及尾状核中都观察到了同位素比率的变化。67Cu摄取的配体需求和饱和动力学的这些相似性确立了大鼠脑中这两种体外铜摄取过程的普遍性。
