Differing functional responses of simple and complex nuclear bodies in uterine luminal epithelial cells following estrogenic stimuli.

Abstract

AbstractA single injection of estradiol or the antiestrogen, nafoxidine, into immature female rats results in a striking divergence in the frequency of observation of nuclear bodies in uterine luminal epithelial cells (Padykula et al., 1981). During the 72 hour period after a single injection of nafoxidine (estrogen antagonist with agonist effects), progressive cellular hypertrophy occurs and is accompanied by a linear increase in the total number of nuclear body profiles (TNB). Conversely, the 72 hour period after a single injection of estradiol is marked by cellular catabolism and a linear decrease in TNB. Our recent demonstration that the population of nuclear bodies consists of two major structural types, simple nuclear bodies (SNB), and complex nuclear bodies (CNB) (Padykula and Pockwinse, pp. 119–130, this volume), permits separation and analysis of the original TNB data in terms of the functional responses of SNB or CNB.During the 72 hour period after injection of nafoxidine, the luminal epithelial cells remain in an anabolic state because the nuclear concentration of estrogen receptor and RNA polymerase activity are elevated. Separate quantitative analysis of the complex and simple nuclear bodies demonstrates two distinct functional responses: (1) a linear increases in the frequency of CNB, and 2) a relatively constant frequency of SNB. Since the complex bodies do not increase in diameter during this period, the increase in the frequency of TNB may arise from an increase in the actual number of CNB per nucleus during cellular hypertrophy.Conversely, a single injection of estradiol results in a relatively short elevation of nuclear estrogen receptor concentration and RNA polymerase activity which returns by 24 hour to the control level. This brief estrogenic stimulation is reflected by a linear decrease in the frequency of TNB and a linear decrease in the frequency of SNB. The frequency of CNB decreases suddenly between 4 and 12 hours and levels off thereafter. The steady decrease in the frequency of observation of nuclear bodies during catabolism may represent a decrease in the actual number of SNB and CNB per nucleus rather than a reduction in their size.This study provides quantitative evidence that simple and complex nuclear bodies are functionally separate entities. Also, some evidence suggests that simple nuclear bodies may be the precursors of complex nuclear bodies.