METABOLISM OF HUMAN BETA-1H - STUDIES IN MAN AND EXPERIMENTAL-ANIMALS

Google Scholar
  • 1 January 1979
    • journal article
    • research article
    • Vol. 38  (3) , 397-404
Abstract
Metabolic studies were performed with a purified, functionally-active preparation of human .beta.1H. In 7 normal human subjects, the half-life was 66-87 h with fractional catabolic rates (FCR) of 1.04-1.63%/h. Synthesis rates were 0.22-0.57 mg/kg per h and extravascular distribution ratios were 0.34-0.67. There was evidence of extravascular catabolism in each subject. In 16 patients with immunological disease, 4 showed hypercatabolism of .beta.1H. Three patients with C3 [complement component 3] nephritic factor (NeF) had normal .beta.1H turnover despite profound reduction in C3 concentration; the reaction of .beta.1H with the .**GRAPHIC**. convertase apparently exposes it to a catabolic site and in the NeF patients the NeF stabilized convertase apparently prevents such exposure. Studies of the acute phase response were performed in 9 patients following elective surgery, with C-reactive protein (CRP) used as the control protein: 6 patients showed no rise in .beta.1H levels and 3 showed a small (20%) rise. All exhibited a gross rise in CRP. Pre-incubation of 125I-.beta.1H with NHS [normal human serum], with NHS in the presence of NeF and with C3b + C3b 1NA [inactivator], caused no change in .beta.1H turnover in animals [rabbit] despite demonstrable total C3 conversion with the NeF.