Effects of rat platelet extracts and human platelet-derived growth factor on megakaryocytopoiesis in vitro

Abstract

An improved plasma clot culture system was developed for the culture of rat megakaryocyte colonies in vitro. Greater stimulation of megakaryocyte colony growth was provided when both serum and plasma were added to the culture medium than when plasma was added alone. Freeze-thawed extracts prepared from 900 x 10(6) platelets/ml saline and also 9 ng/ml of human platelet-derived growth factor (PDGF) caused maximum increases over the controls of 71% and 42%, respectively, in the numbers of megakaryocyte colonies. The increase in the numbers of megakaryocyte colonies induced by platelet extracts and by PDGF implied that substance(s) released by platelets might play an important role in the control of megakaryocytopoiesis.