Binding sites for inositol trisphosphate in the bovine adrenal cortex

Biochem Biophys Res Commun. 1985 Dec 17;133(2):532-8. doi: 10.1016/0006-291x(85)90939-8.


Binding sites for inositol trisphosphate (IP3) have been identified in bovine adrenal cortex, employing [32P]IP3 prepared from human erythrocytes radiolabeled with [32P]ATP. IP3 was bound to adrenal microsomes with high affinity (Kd = 5 nM) and low capacity (186 fmol/mg protein). During kinetic studies, half-maximal binding was reached in less than one min at 4 degrees C, and dissociation was even more rapid with t1/2 of about 10 sec. [32P]IP2 showed no binding to the microsomal sites, which represent putative receptors at which IP3 acts to elevate intracellular calcium concentration during the actions of peptide hormones such as angiotensin II.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenal Cortex / metabolism*
  • Animals
  • Binding Sites
  • Binding, Competitive
  • Cattle
  • Chromatography, Ion Exchange
  • Inositol 1,4,5-Trisphosphate
  • Inositol Phosphates / metabolism*
  • Microsomes / metabolism
  • Radioligand Assay
  • Sugar Phosphates / metabolism*
  • Time Factors


  • Inositol Phosphates
  • Sugar Phosphates
  • Inositol 1,4,5-Trisphosphate