Influence of Estrogen Cytostatics on Activity of Plasma Membrane Enzymes 5'-Nucleotidase and N+-K+-ATPase

We studied the effect of four conjugated synthetic derivatives of estrone and ethynylestradiol and bis-β-chloroethylamine-containing substance on activity of plasma membrane enzymes 5'-nucleotidase and N+-K+-ATPase. As differentiated from precursors, estrogen cytostatics decreased activity of plasma membrane enzymes. Reference preparations chlorophenacyl and estradiol had little effect on activity of 5'-nucleotidase and N+-K+-ATPase. These data suggest that damage to plasma membrane enzymes is related to the effect of estrogen cytostatic molecules. Test compounds produced an antiproliferative effect on estrogen-independent tumor cells, which strongly correlated with a decrease in activity of plasma membrane enzymes 5'-nucleotidase and N+-K+-ATPase. The derivative of ethynylestradiol with the cytostatic residue in the 3-position of the steroid nucleus (Po-714-11a) most significantly modulated enzyme activity.