Effect of prolonged omeprazole administration on segmental intestinal Mg²⁺ absorption in male Sprague-Dawley rats

Fibroblast growth factor‐23 and parathyroid hormone suppress small intestinal magnesium absorption

“…The rate of the total, paracellular, and transcellular Mg 2+ transport of duodenum, jejunum, and ileum was performed as previously described (Suksridechacin et al, 2020 ). In brief, the duodenum, jejunum, and ileum from each rat were dissected into two pieces, which then were mounted onto individually modified Ussing chamber setups.…”

“…After 30, 60, and 120 min, a 100 µL solution was collected from the basolateral and apical sides. The Mg 2+ concentration and the rate of Mg 2+ transport were determined as previously described (Suksridechacin et al, 2020 ). The rate of transcellular Mg 2+ transport in each intestinal segment was calculated by subtracting the rate of total Mg 2+ transport with the rate of paracellular Mg 2+ transport from the same intestinal segment of the individual rats (Suksridechacin et al, 2020 ).…”

“…Dietary intake is the sole source of Mg 2+ ; therefore, bulk absorption of Mg 2+ in the small intestine is vital for health. Previous studies revealed that the duodenum, jejunum, and ileum absorb Mg 2+ through both transcellular and paracellular mechanisms (Suksridechacin et al, 2020 ; Thongon et al, 2016 ). Transcellular Mg 2+ transport proceeds through apical Mg 2+ uptake by transient receptor potential melastatin 6 (TRPM6) and basolateral Mg 2+ extrusion by cyclin and cystathionine β‐synthase domain divalent metal cation transport mediator 4 (CNNM4) (de Baaj et al, 2015 ).…”

“…Transcellular Mg 2+ transport proceeds through apical Mg 2+ uptake by transient receptor potential melastatin 6 (TRPM6) and basolateral Mg 2+ extrusion by cyclin and cystathionine β‐synthase domain divalent metal cation transport mediator 4 (CNNM4) (de Baaj et al, 2015 ). TRPM6 and CNNM4 were markedly expressed in the murine (Suksridechacin et al, 2020 ; Voets et al, 2004 ) and human (Schlingmann et al, 2002 ) small intestine. Currently, the regulatory mechanism of small intestinal Mg 2+ absorption is poorly understood.…”

“…Chronic PTH injection significantly increased intestinal Mg 2+ absorption in rats (Fleet et al, 1994 ) and humans (Hulter & Peterson, 1984 ). Meanwhile, acute PTH exposure may suppress intestinal Mg 2+ absorption through direct activation of mucosal HCO 3 ¯ secretion (Laohapitakworn et al, 2011 ), a reported inhibitory factor for small intestinal Mg 2+ absorption (Suksridechacin et al, 2020 ). Low dietary Mg 2+ intake induced intestinal Mg 2+ absorption (de Baaj et al, 2015 ; Groenestege et al, 2006 ) and subsequently increased circulating FGF‐23 levels (Matsuzaki et al, 2016 ).…”