EFFECTS OF STEROIDAL HORMONES AND TAMOXIP HEN ON PHOSPHOLIPID TURNOVER RATE IN THE TUMOR-CELLS OF THE UTERUS AND BREAST

The cycle of phospholipid turnover has been found to be under the nega tive control of hormonal cytostatics (progesterone) and under the posi tive control of proliferation stimulants (17 beta-estradiol, epidermal growth factor). Specific changes in the synthesis of phospholipids ar e shown when tamoxiphen, an antiestrogen and an inhibitor of protein k inase C, was used. The findings suggest that changes in the turnover r ate of phospholipids are one of the key stages of steroid action on ta rget cells and may be regarded as an additional criterion of tumor gen etic sensibility.