Current opinion on the regulation of small intestinal magnesium absorption

Figure 1 Magnesium absorption in the small intestine through two absorption pathways. The transcellular transport mechanism involves magnesium (Mg²⁺) influx into enterocytes through the transient receptor potential melastatin 6 homodimer channel (TRPM6), transient receptor potential melastatin 7 homodimer channel (TRPM7), and transient receptor potential melastatin 6/7 heterodimer channel (TRPM6/7). Cystathionine β-synthase domain divalent metal cation transport mediator 4 (CNNM4) mediates basolateral Mg²⁺ extrusion by means of secondary active transport. In the paracellular mechanism, Mg²⁺ moves through tight-associated paracellular pores of Claudin 7 (Cldn 7) and Claudin 12 (Cldn 12).