Ontogeny of rat brain and liver glucocorticoid receptors.

Abstract

Glucocorticoid hormone action occurs via a two-step process: Glucocorticoid receptor (GR) forms a cytoplasmic complex with the steroid (G - R complex) which is readily transformed to at least two more basic nucleophilic forms capable of rapid translocation into the nucleus, thereby eliciting a biological response (The transformation - translocation mechanism). Although age dependent differences in the concentration and the properties of rat liver G-R complexes have been reported (Grote et al. 1977), information concerning developing rat brain is limited. A detailed comparative study of GR concentration and G-R complex transformation - translocation effectiveness in the two tissues during development was therefore carried out. Preparation of cytoplasmic GR or G-R complex with [3H]dexamethasone, Scatchard analysis, and column chromatography were carried out as previously described (Alexis et al. 1983). For in vivo nuclear uptake of [3H]dexamethasone, 5 μg per 100 g body weight were injected ip one hour before sacrifice. Labelled