Studies on the Involvement of Lysosomes in Estrogen Action, I

Abstract

Pig endometrium cells, collected by curettage and homogenized in an all-glass Potter Elvehjem homogenizer, gave a considerably higher yield of intact mitochondria and lysosomes than homogenates of whole uterus obtained with the Ultraturrax or the Parr bomb. After homogenization of the cells and subfractionation in the presence of Mg2+, mitochondria and lysosomes equilibrated at the same modal density in isopycnic centrifugation. Homogenization and subfractionation in buffers devoid of divalent cations and containing EDTA resluted in a decrease in the buoyant density of mitochondria, allowing for a separation from lysosomes. The pH optima and the specific activities of 2 mitochondrial enzymes and 8 hydrolyases used as marker enzymes were determined. The morphological characteristics of fractions were established by EM. Preliminary results indicate an involvement of lysosomes in steroid metabolism rather than in steroid and receptor translocation into the nucleus.