Application of a quantitative spectrophotometric endotoxin assay on lymph and plasma from the rat.

A quantitative spectrophotometric assay for endotoxin, utilizing Limulus amebocyte lysate and a chromogenic peptide substrate, was standardized for the application on lymph and plasma from the rat. The influence of inhibitors and unspecific amidolytic activity, the optimal incubation times, the adhesion of endotoxin to platelets and glass surface, the variation in endotoxin standard as well as the effects of cold storage on endotoxin activity were settled. In vitro added as well as endogenously derived endotoxin was studied. The method was found to be reliable when in practical use on these media.