Effect of parathyroid hormone on renal calbindin-D28k.
The present investigation was conducted to examine the effects of parathyroid hormone (PTH) and parathyroid hormone related peptide (PTHrP) on renal calbindin-D28k in rats. Four groups of studies were performed: (1) parathyroidectomy (PTX) or a sham operation followed by infusion of 1,25-dihydroxyvitamin D (1,25[OH]2D) or vehicle; (2) infusions of PTH(1-34), PTH(1-84), 1,25(OH)2D, or vehicle; (3) infusion of PTHrP(1-34), PTHrP (1-86), PTH(1-34), or vehicle; and (4) injections of calcium or vehicle. PTX reduced renal calbindin-D28k levels even when plasma concentrations of 1,25(OH)2D were kept constant by infusion of 1,25(OH)2D. Infusions of PTH(1-34), PTH(1-84), and 1,25(OH)2D all increased renal calbindin-D28k and plasma calcium, whereas PTHrP(1-34) and PTHrP(1-86) increased renal calbindin-D28k before an increase of plasma calcium took place. Hypercalcemia induced by the injection of calcium did not affect the levels of renal calbindin-D28k. The present data suggest that PTH and PTHrP exert a direct effect on renal calbindin-D28k, which is not mediated by changes of 1,25(OH)2D or calcium.
Hemmingsen
C
C
Department of Nephrology, Rigshospitalet, University of Copenhagen, Denmark.
Staun
M
M
Lewin
E
E
Nielsen
P K
PK
Olgaard
K
K
D000818:Animals; D064092:Calbindin 1; D064026:Calbindins; D002117:Calcitriol / Q000494:pharmacology; D003600:Cytosol / Q000187:drug effects* / Q000378:metabolism; D006934:Hypercalcemia / Q000378:metabolism; D007262:Infusions, Intravenous; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010281:Parathyroid Hormone / Q000494:pharmacology*; D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D011506:Proteins / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D064030:S100 Calcium Binding Protein G / Q000378:metabolism*; D019379:Teriparatide / Q000494:pharmacology
C576500:Calb1 protein, rat; D064092:Calbindin 1; D064026:Calbindins; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments; D010455:Peptides; D011506:Proteins; D064030:S100 Calcium Binding Protein G; C068871:parathyroid hormone-related protein (1-86); D019379:Teriparatide; C054296:parathyroid hormone-related protein (1-34); D002117:Calcitriol