To discriminate between the effects of
infection and of
anorexia associated with
infection, liver
albumin synthesis was measured in well-fed rats, in rats injected with live Escherichia coli and in pair-fed rats at different stages of the inflammatory response (1, 6 and 10 days after
infection) using a large dose of l-[1-(14)C]
valine. Albuminaemia and
albumin mRNA levels were unchanged following food restriction. However, absolute
albumin synthesis was decreased in pair-fed rats compared with control animals after 1 day of food restriction, and had returned to normal values by day 10 when food intake was restored.
Infection was characterized by a decrease in the
plasma albumin concentration (35%, 45% and 28% as compared with pair-fed rats at 1, 6 and 10 days after
infection respectively).
Albumin mRNA levels and relative
albumin synthesis were reduced in infected rats as compared with both control and pair-fed animals at all stages of
infection. However, during the early acute response, the
albumin absolute synthesis rate was similar in infected rats and pair-fed rats, indicating no specific effect of
infection at this stage. Later in the course of
infection, the amount of
albumin synthesized by the liver was lower in infected than in pair-fed rats, and hypoalbuminaemia was probably maintained due to a lack of stimulation of synthesis despite increased food intake.