Evidence that production of platelet fibrinogen is synchronous with platelet production in the turpentine-induced acute phase response.
Fibrinogen is synthesized by both hepatocytes and megakaryocytes, and available evidence indicates that cellular production of this protein is controlled by a single gene. We evaluated platelet and plasma fibrinogen production in rats injected with turpentine to induce the acute phase response. After turpentine injection, plasma fibrinogen levels, as expected, rose to more than double the baseline values within 48 hours and then declined to the upper limit of the normal range in 6 days. When levels were expressed as a percentage of total plasma protein, a rise form 4.2% to 10.0% occurred. Thrombocytosis was not observed until day 4; platelet counts returned to the normal range by day 8. The mean fibrinogen content per platelet did not change significantly (P greater than 0.05) during this period of observation. Thus, in contrast to the abrupt rise in the level of plasma fibrinogen, changes in the blood level of platelet fibrinogen paralleled changes in the platelet count. We interpret these findings to indicate that platelet fibrinogen production is synchronized with platelet production by megakaryocytes and thus suggest that fibrinogen production is regulated differently in these cells than it is in hepatocytes.
J E
JE
Williams
J J
JJ
Cypher
M W
MW
Mosesson
D000209:Acute-Phase Proteins; D000818:Animals; D001792:Blood Platelets / Q000166:cytology / Q000378:metabolism*; D001798:Blood Proteins / Q000032:analysis*; D002455:Cell Division; D005340:Fibrinogen / Q000096:biosynthesis*; D007122:Immunoelectrophoresis; D007249:Inflammation / Q000097:blood / Q000139:chemically induced; D008297:Male; D010976:Platelet Count; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014425:Turpentine
D000209:Acute-Phase Proteins; D001798:Blood Proteins; D005340:Fibrinogen; D014425:Turpentine