Uptake of oestradiol by the rabbit hypothalamus. Specificity of binding by nuclei in vitro

Abstract

The binding of [6,7-(3)H]oestradiol-17beta to subcellular fractions of the hypothalamus and the cerebellum of the rabbit was studied in vitro. Uptake of steroid was higher in hypothalamic nuclei than in cerebellar nuclei. Lower binding was observed in other fractions of both tissues. After dialysis of the fractions, hypothalamic nuclei retained a high percentage of oestradiol whereas cerebellar nuclei lost most of the bound steroid. Supernatant fractions of both tissues retained a significant proportion of label after dialysis and after gel filtration on Sephadex G-200. No specific binding was observed in these fractions when subjected to sucrose-density-gradient centrifugation. Purification of nuclei followed by incubation with labelled oestradiol in the absence of the supernatant fraction resulted in loss of binding of steroid by hypothalamic nuclei. Incubation of the purified hypothalamic nuclei with supernatant fraction maintained the binding specificity of hormone retention.

Coital and Estrogen Signals: A Contrast in the Preovulatory Neuroendocrine Networks of Rabbits and Rhesus Monkeys1

“…The anatomical areas of ER protein and mRNA in the above studies were similar to areas reported earlier with use of autoradiographic localization of [H 3 ]estradiol in macaques [132,133]. To our knowledge, there are no reported studies of ER labeling in rabbit brain; however, an early study [134] noted estrogen binding in rabbit hypothalamus. Concentrations of PR, measured by H 3 binding of ORG 2058, are higher in the hypothalamus of the intact female than in adult male and prepubertal female rabbits [135].…”

The Accumulation, Retention and Interaction of Oestradiol and Oestrone in Central Neural and Peripheral Tissues of Gonadectomized Female Rats

“…This differentiation is curious in the light of recent reports which have emphasized the similarities between the molecular properties of the receptors found in the uterus (Jensen, Numata, Smith, Suzuki, Brecher & DeSombre, 1969;Gorski, Shyamala & Toft, 1970), pituitary (Kato, Atsumi & Inaba, 1970;Kato, Atsumi & Muramatsu, 1970;Notides, 1970) and hypothalamus (Chader & Villee, 1970;Eisenfeld, 1970;Kahwanago, Heinrichs & Herrmann, 1970). Since the observed functional differences between the various receptor systems may be the result of minute differences in the molecular properties of the receptors, physical and biochemical methods may not be sensitive to these differences.…”