Megakaryocytic responses to thrombocytopenia and thrombocytosis in Sl/Sld mice
Ebbe, S.; Phalen, E.; D'amore, P.; Howard, D.
Experimental Hematology 6(2): 201-212
1978
ISSN/ISBN: 0301-472X PMID: 627255 Document Number: 132089
S1/S1d mice maintain normal platelet counts in spite of a reduced number of megakaryocytes, but their megakaryocytes are macrocytic. The present studies were done to analyze platelet turnover in the steady state and thrombocytopoietic responses to perturbations of the platelet count. Platelet production, estimated with 35S incorporation in the steady state, blood volume and the total complement of peripheral platelets were normal. S1/S1d mice responded to thrombocytopenia with normal degrees of macromegakaryocytosis and production of macrocytic platelets, but rebound thrombocytosis did not occur. Their megakaryocytes were unusually responsive to transfusion-induced thrombocytosis, showing a prompt and substantial reduction in size. Platelet turnover was normal in undisturbed S1/S1d mice, and feedback regulation occurred. Increased numbers of platelets were not produced in response to stimulation. The megakaryocytes are probably large because of stimulation rather than a direct local effect of the abnormal microenvironment.