Distribution of binding sites for thromboxane A2 in the mouse kidney.

Published

Journal Article

Thromboxane A2 (TxA2) is a potent vasoconstrictor eicosanoid that has been implicated in the pathogenesis of both human and experimental renal diseases. The biological actions of TxA2 in the kidney are mediated through specific cell-surface receptors. In this report, we characterize the distribution of thromboxane receptors (TxR) within the normal mouse kidney by receptor autoradiography. With the iodinated TxR agonist [125I]BOP, TxA2 binding sites were detected throughout the kidney. Competitive inhibition curves of whole kidney binding demonstrated a half-maximal inhibitory concentration of 6.5 nM. When Scatchard analysis was performed on anatomically discrete regions, the [125I]BOP binding in the medulla was best fit by a one-site model, with a dissociation constant (Kd) of 8.2 +/- 2.2 nM. In contrast, [125I]BOP binding in the cortex was better described by a two-site model, with estimated Kd of 262 +/- 16 pM for a higher affinity site and 16.9 +/- 1.3 nM for a lower affinity site. These sites do not appear to represent receptor isoforms that arise from alternative splicing of mRNA. The lower affinity binding sites may represent a novel TxR or an alternative affinity state for the previously characterized high-affinity binding site.

Full Text

Duke Authors

Cited Authors

  • Mannon, RB; Coffman, TM; Mannon, PJ

Published Date

  • December 1996

Published In

Volume / Issue

  • 271 / 6 Pt 2

Start / End Page

  • F1131 - F1138

PubMed ID

  • 8997386

Pubmed Central ID

  • 8997386

Electronic International Standard Serial Number (EISSN)

  • 2163-5773

International Standard Serial Number (ISSN)

  • 0002-9513

Digital Object Identifier (DOI)

  • 10.1152/ajprenal.1996.271.6.f1131

Language

  • eng