Plasma from pregnant rats has anti-tumoural activity

Plasma from 12-day pregnant rats showed a marked anti-tumoural activity when added to short-term cultures of rat Yoshida AH-130 cells. Indeed, 24 h after the addition of 10% pregnant rat plasma resulted in a 34% decrease in cell number as compared with cells without any serum additions or those that were added with virgin plasma. The decrease in cell number was associated with the presence of a marked aneuploid peak, as indicated by flow cytometry analysis, which suggests that pregnant plasma induces apoptosis in this particular tumour cell line. Interestingly, addition of human chorionic gonatrophin to the cell cultures did not exert any effects either on cell content of cell cycle distribution, therefore suggesting that the presence of high concentrations of this hormone in pregnant plasma is unlikely to be the cause of the increased cell death.