Physiological And Metabolic Magnetic Resonance Studies

核磁共振方法为研究完整系统、灌流器官、细胞悬浮液中的代谢和生理过程以及通过检查细胞提取物提供了一种独特的方法。该项目研究化学毒素或物理因素如何改变新陈代谢过程，主要侧重于灌流的小鼠心脏制剂。研究的重点是细胞内离子，但也对其他细胞代谢物进行了评估。已有研究表明，在缺血损伤前心脏受到应激的情况下，与男性相比，女性对缺血/再灌注损伤的保护作用更强(Cross H，Murphy E，Steenbergen C)。钙负荷和肾上腺素能刺激揭示了男性和女性对缺血-再灌注损伤的敏感性差异。上午好。J.Physiol.2002年；283：H481-H489)。最近使用不同表达α或β雌激素受体的转基因小鼠的研究表明，β雌激素受体对女性心脏的缺血/再灌注损伤具有保护作用。 第二个研究领域侧重于确定硼酸盐发挥生理和毒理作用的机制。我们之前证明了硼酸盐和丝氨酸的结合通过形成一个三元复合体来抑制酶-谷氨酰转肽酶，并证明了该复合体的硼酸盐类似物L-2-氨基-4-硼酸丁酸比1：1的丝氨酸-硼酸盐混合物抑制该酶的效力要强得多。这一结果表明，三元络合物的普遍参与可能是硼酸盐的生理和毒理作用的基础。我们最近用核磁共振光谱和X射线结晶学表征了其他由硼酸盐、醇和胰酶形成的三元络合物的结构。除了这些研究提供的对硼酸盐生物化学和毒理学的基本见解外，他们还提出了开发基于硼酸盐的生物功能效应器的方法。

NMR methods provide a unique approach for the investigation of metabolic and physiological processes in intact systems, perfused organs, cell suspensions, as well as by examination of cell extracts. This project investigates how chemical toxins or physical factors alter metabolic processes, with primary emphasis on perfused mouse heart preparations. Studies have focused on intracellular ions, but other cellular metabolites are also evaluated. It has been shown previously that under conditions in which hearts are stressed prior to an ischemic insult, females exhibit greater protection from ischemia/reperfusion injury compared with males (Cross H, Murphy E, Steenbergen C. Ca2+ loading and adrenergic stimulation reveal male/female differences in susceptibility to ischemia-reperfusion injury. Am. J. Physiol. 2002;283:H481-H489). Recent studies using transgenic mice with different expression of the alpha or beta estrogen receptor demonstrated that the beta estrogen receptor was responsible for the protection from ischemia/reperfusion injury seen in the female hearts. A second area of research has focused on determining the mechanisms by which borate exerts physiological and toxicological effects. We previously demonstrated that the combination of borate and serine inhibits the enzyme gamma-glutamyl transpeptidase via the formation of a ternary complex, and demonstrated that a boronate analog of this complex, L-2-amino-4-borono butanoic acid, inhibits this enzyme with much greater potency than a 1:1 serine-borate mixture. This result suggests the possibility of a general involvement of ternary complexes as the basis for the physiological and toxicological effects of borate. We have recently characterized the structures of other ternary complexes formed from borate, alcohols, and trypsin, using both NMR spectroscopy and X-ray crystallography. In addition to the fundamental insight into borate biochemistry and toxicology that these studies provide, they suggest approaches for the development of boronate-based effectors of biological function.