Université Paris-Descartes, Sorbonne Paris-Cité, F-75006 Paris, France.
Annu Rev Physiol. 2014;76:411-30. doi: 10.1146/annurev-physiol-021113-170336.
Magnesium's most important role is in the release of chemical energy. Although most magnesium is stored outside of the extracellular fluid compartment, the regulated value is blood magnesium concentration. Cellular magnesium and bone magnesium do not play a major role in the defense of blood magnesium concentration; the major role is played by the kidney, where the renal tubule matches the urinary magnesium excretion and the net entry of magnesium into the extracellular fluid. In the kidney, magnesium is reabsorbed in the proximal tubule, the thick ascending limb of the loop of Henle, and the distal convoluted tubule. Magnesium absorption is mainly paracellular in the proximal tubule and in the thick ascending limb of the loop of Henle, whereas it is transcellular in the distal convoluted tubule. Several hormones and extracellular magnesium itself alter the distal tubular handling of magnesium, but the hormone(s) regulating extracellular magnesium concentration remains unknown.
镁最重要的作用是释放化学能。尽管大部分镁储存在细胞外液隔间之外，但受调节的是血镁浓度。细胞内镁和骨镁在维持血镁浓度稳定方面不起主要作用；主要作用是由肾脏完成的，肾脏肾小管将尿镁排泄和镁向细胞外液的净内流相匹配。在肾脏中，镁在近端小管、Henle 袢升支粗段和远曲小管中被重吸收。镁的吸收在近端小管和 Henle 袢升支粗段主要是细胞旁途径，而在远曲小管则是细胞内途径。一些激素和细胞外镁本身改变了远端肾小管对镁的处理，但调节细胞外镁浓度的激素尚不清楚。
