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Abstract Prostaglandins have diverse effects on renal electrolyte reabsorption, inhibiting NaCl absorption in the thick ascending limb and modulating sodium and calcium transport in cortical collecting cells. It is unclear what effect, if any, prostaglandins have on tubular magnesium handling. The effects of prostaglandin E2 (PGE2) were studied on immortalized mouse distal convoluted tubule (MDCT) cells by measuring cellular cAMP formation with radioimmunoassays and Mg21 uptake with fluorescence techniques. Intracellular free Mg21 concentration ([Mg21]i) was measured on single MDCT cells using microfluorescence with mag-fura 2. To assess Mg21 uptake, MDCT cells were first Mg21 depleted to 0.22 6 0.01 mM by culturing in Mg21-free media for 16 h and then placed in 1.5 mM MgCl2, and the changes in [Mg21]i were determined. [Mg21]i returned to basal levels, 0.53 6 0.02 mM, with a mean refill rate, d([Mg21]i)/dt, of 173 6 8 nM/s. Indomethacin, 5 μM, diminished basal Mg21 uptake, suggesting that endogenous prostaglandins may stimulate Mg21 entry in control cells. PGE2 stimulated Mg21 entry in a concentration-dependent manner with maximal response of 311 6 12 nM/s, at a concentration of 1027 M, which represented an 80 6 3% increase in uptake rate above control values. This was associated with a sixfold increase in intracellular cAMP generation. PGE2-stimulated Mg21 uptake was completely inhibited with the Rp diastereoisomer of adenosine 38,58-cyclic monophosphothionate (RpcAMPS), a protein kinaseAinhibitor, and U-73122, a phospholipase C inhibitor, and partially by chelerythrine, a protein kinase C inhibitor. Accordingly, PGE2-mediated Mg21 entry rates involve multiple intracellular signaling pathways. These studies demonstrate that PGE2 stimulates Mg21 uptake in a cell line of MDCT.

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