Effects of magnesium on renal and intestinal calbindin-D.
The possible effects of magnesium on the vitamin D-dependent renal and intestinal calbindin-D were investigated. In a low magnesium model 70 Wistar rats were allocated to either a normomagnesemic diet (Mg 3.2 g/kg) or a Mg-deficient diet (Mg 0.18 g/kg) for 10 or 24 days. The rats had intraperitoneal injections of 1,25-(OH)2 vitamin D3 0.2 microgram, MgSO4 100 mumol or placebo daily for the last 4 days. In a high magnesium model 60 Wistar rats were allocated to three groups on a normomagnesemic diet supplied with intraperitoneal MgSO4 20 mumol, 100 mumol or placebo daily. Half of the animals in each group were further supplied with intraperitoneal 1,25-(OH)2 vitamin D3 0.2 micrograms daily. The concentrations of intestinal calbindin-D9k increased on the low Mg diet from 1.6 (1.1-2.0) to 2.7 (2.0-2.9) micrograms/mg protein (p < 0.02), but were unchanged in the high Mg groups. Vitamin D treatment raised the levels of calbindin-D9k in the normomagnesemic group (p < 0.01), but not significantly in the low Mg group. Administration of MgSO4 to the low Mg rats normalized the elevated levels of intestinal calbindin-D9k (p < 0.05). The concentrations of renal calbindin-D28k were not changed by the low Mg diet, but were lower in the high Mg group [0.8 (0.6-1.1) micrograms/mg protein] than in the control group [1.5 (1.1-1.8) micrograms/mg protein; p < 0.05]. Animals in the low, high and normal magnesium group showed no differences in plasma concentrations of 1,25-(OH)2 vitamin D.(ABSTRACT TRUNCATED AT 250 WORDS)
Hemmingsen
C
C
Department of Nephrology, Rigshospitalet, University of Copenhagen, Denmark.
Staun
M
M
Olgaard
K
K
D000818:Animals; D064092:Calbindin 1; D064026:Calbindins; D002116:Calcitonin / Q000097:blood; D002117:Calcitriol / Q000008:administration & dosage / Q000097:blood; D002118:Calcium / Q000097:blood / Q000652:urine; D003404:Creatinine / Q000097:blood; D004032:Diet; D004386:Duodenum; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism*; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008274:Magnesium / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology* / Q000652:urine; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D064030:S100 Calcium Binding Protein G / Q000378:metabolism*; D014508:Urea / Q000097:blood
C576500:Calb1 protein, rat; D064092:Calbindin 1; D064026:Calbindins; D010281:Parathyroid Hormone; D064030:S100 Calcium Binding Protein G; C576508:S100g protein, rat; D010758:Phosphorus; D014508:Urea; D002116:Calcitonin; D003404:Creatinine; D002117:Calcitriol; D008274:Magnesium; D002118:Calcium