Solubilization and characterization of lactogenic hormone receptor from kidney of lactating cow

G. Elberg, A. Ashkenazi, A. Gertler*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Solubilization of the microsomal fraction from bovine kidney by Triton X-100 or by 3-[(3-cholamidopropyl)-dimethylammonio] 1-propanesulfonate (CHAPS) increased 2-fold the thermodynamic association constant for hGH. While Solubilization with CHAPS did not change the 13-fold preferential binding of human growth hormone (hGH) over ovine prolactin (oPRL), solubilization with Triton X-100 increased this preference to 47-fold. The binding was optimal at pH 7-7.5 in the presence of 10 mM of MgCl2 or CaCI2. The association rate with hGH was identical in the microsomal and Triton X-100 solubilized fractions but the dissociation was slower in the latter. Only partial dissociation was observed at neutral pH. Full dissociation was, however, achieved by lowering the pH to 4-5, indicating that the binding was not covalent. Gel filtration studies of the Triton X-100 solubilized fraction after preincubation in the presence of reducing agent revealed two sharp peaks of activity, one having Mr of > 700 kDa that represented the aggregated receptor, and the second, with Mr. 110-115 kDa. The specificity of the partially purified receptors clearly shows that they are lactogenic and not somatogenic. They resemble lactogenic receptors found in other bovine organs, but differ from other species particularly in their differential affinities of PRL and hGH.

Original languageEnglish
Pages (from-to)77-85
Number of pages9
JournalMolecular and Cellular Endocrinology
Volume61
Issue number1
DOIs
StatePublished - Jan 1989

Keywords

  • bovine
  • Human growth hormone
  • Kidney
  • Prolactin receptor

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