Testosterone-induced nuclear changes in the rat uterine luminal epithelium. A stereological study

Testosterone administration to the spayed immature female rat produces significant changes in the nuclear ultrastructure of the uterine epithelial cells. In general, these changes increase when a higher dose is used. The most intense changes occur in the nucleolus: volume density and volume increase; volume increases in all nucleolar compartments; granular and vacuolar volume density increase; fibrillar center number increase, but a reduction of their individual volume is observed. Condensed chromatin volume density and volume decrease. Nuclear volume, nuclear envelope surface, and nuclear body volume density and frequency remain almost the same. The surface density of the interface between condensed and dispersed chromatin, fibrillar centers and fibrillar component, and condensed chromatin and fibrillar component, show significant variations even with a small dose of testosterone (0.5 mg). Such a dose is unable to change the volume density of condensed chromatin or fibrillar centers. Correlations between our results and biochemical or other morphological data are discussed.