Etiocholanolone receptor in rat liver and novikoff rat hepatoma cell culture

A. I. Adigweme, Yusuf J Abul-Hajj

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

The binding of tritiated etiocholanolone to rat liver and Novikoff hepatoma cells has been investigated. Cytosols obtained from rat liver and Novikoff hepatoma contain high affinity-low capacity binding macromolecules (Kd = 9.6 × 10-10 M for rat liver and 1.1 × 10-9 M for Novikoff hepatoma and the number of binding sites was 64 fmol/mg protein for rat liver and 76 fmol/mg protein for Novikoff hepatoma). Cytosols labelled with [3H]-etiocholanolone had a sedimentation coefficient of 4.6 under low and high salt concentration. Preincubation of rat liver slices and Novikoff hepatoma cells with unlabelled etiocholanolone followed by exchange of nuclear receptor complex with [3H]-etiocholanolone showed the presence of a single peak sedimenting at 4.6 S. Extraction of nuclear receptor peak sedimenting at 4.6 S and identification of the steroid showed that 86% of the radioactivity was associated with etiocholanolone and 14% with 5β-androstane-3α,17β-diol. Competition studies showed that steroids with 5β-H configuration were very effective in displacing etiocholanolone from cytoplasmic receptors while steroids with the 5α-configuration were not. These studies show that etiocholanolone receptor present in mammalian liver is essentially similar to that obtained from chick embryo liver.

Original languageEnglish (US)
Pages (from-to)867-875
Number of pages9
JournalJournal of Steroid Biochemistry
Volume14
Issue number9
DOIs
StatePublished - Sep 1981

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