Insulin stimulates Mg2+ uptake in mouse distal convoluted tubule cells

Dai LJ, Bapty BW, Ritchie G, Kerstan D, and Quamme GA: Insulin stimulates Mg2+ uptake in  mouse distal convoluted tubule cells. American Journal of Physiology 277:F907-F913, 1999.

PDF Download paper

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.

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.
intracellular magnesium; fluorescence

Bookmark and Share

Tags: , , , , , ,



This entry was posted on Friday, September 11th, 2009 at 9:09 pm and is filed under Nephrology. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

Leave a Reply