The angiotensin II receptor of rabbit liver: characterization in isolated hepatocytes and effect of GTP

J Endocrinol. 1989 Oct;123(1):131-6. doi: 10.1677/joe.0.1230131.

Abstract

A homologous population of specific angiotensin II receptors is present on the cell surface of isolated rabbit hepatocytes. The binding characteristics of [3H]angiotensin II to the cells were: association rate constant (K+1) 0.08 l/nmol per min and dissociation rate constant (K-1) 1.9/min, yielding a dissociation constant (Kd) of 24 nmol/l. A very similar Kd (32 nmol/l) has been derived from saturation binding data which indicate a maximal binding capacity of about 200,000 sites/cell. Analysis of the association binding data to purified liver plasma membranes indicated a Kd of 6 nmol/l in the absence and 30 nmol/l in the presence of GTP. Dissociation was clearly dependent upon the presence of the nucleotide, which shifted the K-1 from 0.12/min to 0.42/min. The studied binding sites are very likely to be involved in the glycogenolytic action of angiotensin II, since a highly significant correlation was established between the biological activity (activation of glycogen phosphorylase) and the binding affinity of a series of agonistic analogues. The reported characteristics of the rabbit hepatic angiotensin II receptors show much similarity with those of rat liver.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II / metabolism*
  • Animals
  • Cells, Cultured
  • Guanosine Triphosphate / pharmacology*
  • Kinetics
  • Liver / metabolism*
  • Rabbits
  • Receptors, Angiotensin / drug effects
  • Receptors, Angiotensin / metabolism*
  • Time Factors

Substances

  • Receptors, Angiotensin
  • Angiotensin II
  • Guanosine Triphosphate