Glucocorticoid receptors in developing rat brain and liver

Glucocorticoid receptor complex from developing liver and brain was shown to be capable of binding to isolated adult liver nuclei after in vitro activation, and nuclear binding capacity was observed in experiments in vivo while values peaked during the second week, in both tissues studied.

Abstract

Dexamethasone receptors were measured by conventional equilibrium steroid binding studies in rat liver and brain cytosol, during late prenatal and postnatal development, Receptor binding could be detected in both cytosol preparations as early as the 17th day of gestation. Receptor levels in the cytosol from intact animals reached adult values by the 1st day after birth in both tissues. Using adrenalectomized animals an increase which reached adult values was observed during the first postnatal week for liver and the second postnatal week for brain. At physiological concentrations of endogenous glucocorticoids depletion of receptor from the cytosol of intact animals was minimal at postnatal day 1 and reached adult levels by day 7. Chromatographic analysis in DEAE-Sephadex A50 minicolumns of unactivated and activated receptor constituents revealed the same pattern as that of adult animals. Glucocorticoid receptor complex from developing liver and brain was shown to be capable of binding to isolated adult liver nuclei after in vitro activation. However full capacity, for nuclear binding was observed in vivo, after injection of inducing doses of [3H]dexamethasone: By the end of the first week after birth adult nuclear binding capacity was observed in experiments in vivo while values peaked during the second week, in both tissues studied.