title: Methylprednisolone affects inhibitors of the complement and the contact systems; functional and immunochemical studies on alpha 2-macroglobulin and C1 inhibitor.
abstract: The effects of methylprednisolone sodium succinate (MP) on main inhibitors of the classical pathway of complement and on the contact system were studied in citrated pool plasma. Endotoxin (2.10(9) ng/l, lipopolysaccharide B, E. coli 026: B6 Difco Laboratories, Detroit, Michigan, USA) and/or MP in doses of 0.1, 1, 5 and 10 mg/ml were incubated with plasma at 37 degrees C. Plasma samples were obtained at timed intervals up to 24 hours for determination of C1 inhibitor (C1inh) and alpha 2-macroglobulin (alpha 2M) values using both functional and immunochemical assays. Plasma containing endotoxin without MP revealed decreases of C1inh and alpha 2M values after 12 hours. Addition of MP in high doses (10 mg/ml) gave an additive effect on the endotoxin-induced decreases of C1inh and alpha 2M values, evident 1 and 12 hours after the beginning of incubation, respectively. When MP alone was added to plasma (5 and 10 mg/ml) also significant decreases in C1inh and alpha 2M values were seen. MP in low doses (0.1 and 1 mg/ml) did not either influence the endotoxin-induced changes in the protease inhibitor functions, or induce significant changes in C1inh and alpha 2M values when incubated in plasma without endotoxin. This study demonstrates that MP in high doses induces marked decreases in plasma C1inh and alpha 2M inhibitory functions and that MP has an additive effect on the endotoxin-induced decreases of these inhibitors.
authors: Department of Surgery, University of Oslo, Norway.
authors: O
authors: O
authors: Roeise
authors: J O
authors: JO
authors: Stadaas
authors: A O
authors: AO
authors: Aasen
mesh_terms: D001769:Blood / Q000187:drug effects; D001790:Blood Physiological Phenomena; D003174:Complement C1 Inactivator Proteins / Q000378:metabolism*; D003171:Complement Pathway, Classical / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000494:pharmacology; D006801:Humans; D007120:Immunochemistry; D066298:In Vitro Techniques; D008775:Methylprednisolone / Q000008:administration & dosage / Q000494:pharmacology*; D000511:alpha-Macroglobulins / Q000378:metabolism*
chemical_list: D003174:Complement C1 Inactivator Proteins; D004731:Endotoxins; D000511:alpha-Macroglobulins; D008775:Methylprednisolone