Renal magnesium transport and the effects of hypermagnesemia, hypercalcemia, body magnesium stores and parathyroid hormone.

Magnesium reabsorption occurs throughout the proximal, loop and distal segments of the nephron. The proximal tubule is less permeable to magnesium than calcium and sodium and most of the filtered load is reclaimed in the thick ascending limb of the loop of Henle. Thus one would expect that factors which regulate magnesium reabsorption should act within this important segment. No single hormone or agent appears to regulate magnesium reabsorption sufficiently to account for urinary changes; rather it appears to be a number of intracellular and extracellular factors acting in concert to effect day to day magnesium homeostasis.