Decrease in the number of platelets and megakaryocytes following tumor inhibition by chronic foot shock stress

The effects of tumor growth and its modulation on hosts' megakaryocytopoies is and platelet production were evaluated in mice bearing Sarcoma-180 (S-18 0) tumor. Tumor bearers had an increased number of mature megakaryocytes (M K), immature cells (SAChE(+) cells), and MK stem cells. Platelet production , assessed in terms of (SeM)-Se-75 incorporation into circulating platelets , was also enhanced resulting in an increased blood platelet count. Tumor; bearing animals subjected to chronic foot shock (CFS) stress had a reduced tumor burden, depleted number of MKs and their progenitors, and diminished platelet production. The results show that S-180 tumor growth has stimulato ry effect on hosts' platelet production and the magnitude of this effect wa s related to the extent of tumor burden.