These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Pathways involved in PTH-induced rise in cytosolic Ca2+ concentration of rat renal proximal tubule.
    Author: Tanaka H, Smogorzewski M, Koss M, Massry SG.
    Journal: Am J Physiol; 1995 Feb; 268(2 Pt 2):F330-7. PubMed ID: 7864174.
    Abstract:
    Parathyroid hormone (PTH) raises cytosolic Ca2+ concentration ([Ca2+]i) in isolated or cultured renal proximal tubule cells. The pathways through which this action is mediated are not fully delineated. This study explored these pathways utilizing fura 2. [Ca2+]i of freshly prepared renal proximal tubular cells increased from 150 +/- 3.6 to 281 +/- 9.0 nM after the exposure to 10(-7) M angiotensin II, which served as a positive control. Both PTH-(1-84) and PTH-(1-34) produced a dose-dependent rise in [Ca2+]i. The effects of both moieties were similar up to 10(-7) M, but with higher doses the rise in [Ca2+]i with PTH-(1-84) was greater (P < 0.01) than with PTH-(1-34). This effect of the hormone occurred in the presence or absence of calcium in the media, but the rise in [Ca2+]i was significantly greater in the presence of calcium. The PTH-induced rise in [Ca2+]i was markedly inhibited by PTH antagonist [Nle8,18,Tyr34]bPTH-(7-34)-NH2 (bPTH is bovine PTH), verapamil, or nifedipine. 12-O-tetradecanoylphorbol-13-acetate (TPA), an activator of protein kinase C, increased [Ca2+]i of cells, but its effect was less than PTH. Staurosporine abolished the TPA effect and partially inhibited that of PTH. A G protein activator raised [Ca2+]i, whereas a G protein inhibitor and pertussis toxin partially blocked the effect of PTH. Sodium or chloride channel blockers or sodium-free media did not modify the effect of PTH.(ABSTRACT TRUNCATED AT 250 WORDS)
    [Abstract] [Full Text] [Related] [New Search]