Piscine PTHrP regulation of calcium and phosphate transport in winter flounder renal proximal tubule primary cultures. | - CCMAR -

Journal Article

TítuloPiscine PTHrP regulation of calcium and phosphate transport in winter flounder renal proximal tubule primary cultures.
Publication TypeJournal Article
AuthorsGuerreiro, PM, Canario, AVM, Power, DM, J Renfro, L
Year of Publication2010
JournalAm J Physiol Regul Integr Comp Physiol
Date Published2010 Aug
Palavras-chaveAnimals, Biological Transport, Calcium, Cells, Cultured, Electric Impedance, Fish Proteins, Flounder, Gene Expression Regulation, Indoles, Kidney Tubules, Proximal, Kinetics, Maleimides, Membrane Potentials, Parathyroid Hormone-Related Protein, Peptide Fragments, Phosphates, Protein Kinase C, Protein Kinase Inhibitors, Receptor, Parathyroid Hormone, Type 1, RNA, Messenger, Sodium-Phosphate Cotransporter Proteins, Type II

Multiple factors control calcium (Ca(2+)) and inorganic phosphate (P(i)) transport in the fish nephron, and the recently discovered members of the piscine parathyroid hormone-like protein family are likely participants in such regulatory mechanisms. The effects of an NH(2)-terminal peptide (amino acids 1-34) of Takifugu rubripes parathyroid hormone-related protein, (1-34)PTHrP, on Ca(2+) and P(i) transport were investigated in winter flounder (Pseudopleuronectes americanus) proximal tubule cells in primary culture (fPTCs). RT-PCR performed on RNA extracted from fPTCs and from intact kidney tissue indicated that expression of PTHrP and types 1 and 3 PTH/PTHrP receptors occurred both in vivo and in vitro and that circulating levels of PTHrP measured by specific radioimmunoassay averaged 2.5 +/- 0.13 ng/ml. fPTC monolayers were mounted in Ussing chambers, and under neutral electrochemical conditions, addition of 10 nM (1-34)PTHrP to the basolateral side induced a slight increase in Ca(2+) transport rate from luminal to peritubular side, significantly stimulating net Ca(2+) reabsorption. (1-34)PTHrP also significantly increased the P(i) secretory flux, and slightly reduced P(i) reabsorption, evoking a significant increase in P(i) net secretion. This stimulatory effect was partially inhibited by bisindolylmaleimide, an inhibitor of protein kinase C. Incubation of ex vivo flounder renal tubules with (1-34)PTHrP resulted in apparent reduction of Na(+)-P(i) cotransporter type II (NaP(i)-II) protein in tubule membranes. PTHrP seems therefore to participate in the modulation of Ca(2+) and P(i) homeostasis by fish kidney.



Alternate JournalAm. J. Physiol. Regul. Integr. Comp. Physiol.
PubMed ID20484696
CCMAR Authors