Specific Binding of ³H-Estradiol to the Cytosol of Rat Pancreas and Uterus: Bound Sites In Pancreatic Extracts Do Not Translocate ³H-Estradiol to Nuclei Suggesting A Basic Difference In Mode of Action

Abstract

In parallel sets of experiments, cytosol fractions from rat pancreas and uterus were incubated with 2 nM ³H-estradiol in the presence or absence of nuclei from pancreas and liver. After incubation for 1 hr at room temperature, the nuclei were removed by centrifugation and specific binding determined in the cytosol fractions as well as in the separated nuclei. The protein that binds ³H-estradiol in uterine extracts translocated the hormone to nuclei of pancreas and liver while the one in pancreas was devoid of this activity. It is presumed, therefore, that modification of trancription is not a primary action of the steroid-bound complex in pancreas.