Studies on the interrelationship among serum estrogen levels, estrogen receptors (unbound cytoplasmic, bound cytoplasmic and bound nuclear), RNA syntheses and protein syntheses in the normal endometrial tissues (author's transl)

Abstract

The physiological effects of estrogen on normal human endometrial tissues were investigated. In the experimental animal uterus, it was well established that the first response to estrogen required RNA synthesis which then led to protein synthesis.The aim of this investigation was to study the interrelationships among the serum estrogen levels, estrogen receptors (unbound cytoplasmic, bound cytoplasmic and bound nuclear), RNA syntheses and protein syntheses in normal human endometrial tissues.The unbound cytoplasmic estrogen receptors were measured by the D.C.C. method, and bound cytoplasmic and nuclear estrogen receptors were measured by the protamine exchange method.1) The unbound and bound estrogen receptor concentrations of the cytoplasmic fraction of normal human endometrial tissues were increased progressively throughout the proliferative phase, and were at their highest in the secretory phase and in the late secretory phase of the cycle.2) The bound estrogen receptor concentrations of the nuclear fraction were highest in the late proliferative phase and lowest in the early secretory phase, but increased throughout the secretory phase.3) RNA syntheses were increased progressively throughout the proliferative phase and highest in the late proliferative phase and lowest in the late secretory phase.4) Protein syntheses were also highest in the late proliferative phase and lowest in the early secretory phase, but increased throughout the secretory phase.5) The serum estrogen levels have a positive correlationship with unbound cytoplasmic receptors (r=0.85), bound cytoplasmic receptors (r=0.79) and bound nuclear receptors (r=0.70) in the proliferative phase, and a low positive correlationship with unbound cytoplasmic receptors (r=0.66) and bound cytoplasmic receptors (r=0.50), but no correlationship was found with bound nuclear receptors in the secretory phase.6) The serum estrogen levels have a positive correlationship with RNA syntheses (r=0.86) and protein syntheses (r=0.84) in the proliferative phase, but no correlationship was found in the secretory phase.7) RNA syntheses in the endometrium have a positive correlationship with unbound cytoplasmic receptors (r=0.88), bound cytoplasmic receptors (r=0.80) and bound nuclear receptors (r=0.79) in the proliferative phase, but in the secretory phase, these have a positive correlationship only with bound cytoplasmic receptors (r=0.69).8) Protein syntheses in the endometrium have a positive correlationship with unbound cytoplasmic receptors (r=0.61), bound cytoplasmic receptors (r=0.68) and bound nuclear receptors (r=0.83) in the proliferative phase, and a positive correlationship only with bound nuclear receptors (r=0.61) in the secretory phase.