title: Hyperphosphatemia, hypocalcemia and increased serum potassium concentration as distinctive features of early hypomagnesemia in magnesium-deprived mice.
abstract: Magnesium-deficient patients show dysfunctional calcium (Ca(2+)) metabolism due to defective parathyroid hormone (PTH) secretion. In mice and rats, long-term magnesium (Mg(2+)) deprivation causes hyperphosphaturia and increases fibroblast growth factor 23 (FGF23) secretion, despite normal serum phosphate (Pi) and Ca(2+). Electrolyte disturbances during early hypomagnesemia may explain the response of mice to long-term Mg(2+) deprivation, but our knowledge of electrolyte homeostasis during this stage is limited. This study compares the effect of both short- and long-term Mg(2+) restriction on the electrolyte balance in mice. Mice were fed control or Mg(2+)-deficient diets for one to three days, one week, or three weeks. Prior to killing the mice, urine was collected over 24 h using metabolic cages. Within 24 h of Mg(2+) deprivation, hypomagnesemia, hypocalcemia and hyperphosphatemia developed, and after three days of Mg(2+) deprivation, serum potassium (K(+)) was increased. These changes were accompanied by a reduction in urinary volume, hyperphosphaturia, hypocalciuria and decreased Mg(2+), sodium (Na(+)) and K(+) excretion. Surprisingly, after one week of Mg(2+) deprivation, serum K(+), Pi and Ca(2+) had normalized, showing that mineral homeostasis is most affected during early hypomagnesemia. Serum Pi and K(+) are known to stimulate secretion of FGF23 and aldosterone, which are usually elevated during Mg(2+) deficiency. Thus, the hyperphosphatemia and increased serum K(+) concentration observed during short-term Mg(2+) deprivation may help our understanding of adaptation to chronic Mg(2+) deficiency.
authors.affiliation: Department of Biology, The College at Brockport, State University of New York, 350 New Campus Drive, Brockport, NY 14420, USA.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Ortega
authors.affiliation: Department of Biology, The College at Brockport, State University of New York, 350 New Campus Drive, Brockport, NY 14420, USA.
authors.forename: Jacob R
authors.initials: JR
authors.lastname: MacWilliams
authors.affiliation: Department of Biology, The College at Brockport, State University of New York, 350 New Campus Drive, Brockport, NY 14420, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Dey
authors.affiliation: Department of Biology, The College at Brockport, State University of New York, 350 New Campus Drive, Brockport, NY 14420, USA.
authors.forename: Valerie B
authors.initials: VB
authors.lastname: Courtright
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001835:Body Weight; D002118:Calcium / Q000097:blood* / Q000652:urine; D004195:Disease Models, Animal; D000089703:Fibroblast Growth Factor-23; D006947:Hyperkalemia / Q000097:blood / Q000209:etiology* / Q000503:physiopathology / Q000652:urine; D054559:Hyperphosphatemia / Q000097:blood / Q000209:etiology* / Q000503:physiopathology / Q000652:urine; D006996:Hypocalcemia / Q000097:blood / Q000209:etiology* / Q000503:physiopathology / Q000652:urine; D008274:Magnesium / Q000097:blood* / Q000652:urine; D008275:Magnesium Deficiency / Q000097:blood / Q000150:complications* / Q000503:physiopathology / Q000652:urine; D008297:Male; D008810:Mice, Inbred C57BL; D010710:Phosphates / Q000097:blood* / Q000652:urine; D011188:Potassium / Q000097:blood* / Q000652:urine; D013997:Time Factors; D014882:Water-Electrolyte Balance
chemical_list: D015415:Biomarkers; C000717428:Fgf23 protein, mouse; D010710:Phosphates; D000089703:Fibroblast Growth Factor-23; D008274:Magnesium; D011188:Potassium; D002118:Calcium
keywords: hyperphosphatemia; hypocalcemia; magnesium deficiency; mice; plasma potassium