Recombinant human interleukin-1β decreases serum carboxypeptidase N and modifies serum amino acid concentrations in rats

Abstract

The effects of recombinant human interleukin-1β (rhIL-1β) on various serum constitutents were studied following subcutaneous injection (12.5 or 125 μg/kg) in female Wistar rats. Protein electrophoresis and the determination of the serum concentrations of carboxypeptidase N (CPN), aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, aldolase, total proteins, iron, urea, creatinine, and several amino acids were performed 12, 24, and 72 hr after injection. With both doses of rhIL-1β, iron, albumin, CPN, and lysine were significantly decreased whereas α 2-globulin, urea, and creatinine were significantly increased 12 hr after administration. Iron and CPN were still low after 24 hr but returned to normal levels after 72 hr. With the higher dose of rhIL-1β, only alanine and phenylalanine levels were increased after 12 and 72 hr, taurine after 12 hr, and methionine after 24 hr. There were no biochemical or histological signs of hepatotoxicity. The findings indicate that rhIL-1β produces a reversible alteration of various biochemical plasma constituents without any apparent signs of cytotoxicity. Moreover, the decrease in CPN observed may influence the degradation of inflammatory peptides.