Summary
The effect of pharmacologic doses of adrenal corticosteroids upon plasma fibrinogen
level, incorporation of 75Se-Methionine (75SeM) into fibrinogen, and disappearance of plasma 125I-fibrinogen was evaluated in rabbits. Single 25 mg doses of hydrocortisone or cortisone
transiently increased both 75SeM incorporation into fibrinogen and plasma fibrinogen levels, but 1 to 5 mg doses
of hydrocortisone had no significant effect upon plasma fibrinogen levels. Repeated
daily injections of 25 mg of hydrocortisone did not increase plasma fibrinogen levels
progressively. Two doses of 25 mg of hydrocortisone, given 24 hr apart, failed to
alter the rate of disappearance of plasma 125I-fibrinogen radioactivity, i.e., plasma fibrinogen catabolism. Intramuscular injection
of 2.5 ml of propylene glycol solvent caused a prolonged rise in plasma fibrinogen
level, whereas injection of 25 mg of corticosterone dissolved in propylene glycol
resulted in an attenuated and transient rise in plasma fibrinogen level. Apparently,
the presence or absence of a coexistent inflammatory stimulus determines the overall
effect of large pharmacologic doses of corticosteroids upon fibrinogen metabolism
in the rabbit. In the presence of inflammation, corticosteroids decrease synthesis
with a resultant fall in plasma fibrinogen level; in the absence of inflammation,
corticosteroids may increase synthesis transiently with a resultant slight increase
in plasma fibrinogen level.
