(1-->3)-beta-D-glucan determination in rat organs with limulus coagulation factor G

One cause of a false positive limulus test after surgery or hemodialysis has been identified as extrinsic (1-->3)-beta-D-glucan which was derived from surgical gauze or cellulose dialyzer. However, there have been no investigations concerning intrinsic factors and the presence of (1-->3)-beta-D-glucan in mammalian organs. In this study, (1-->3)-beta-D-glucan in homogenate of various rat organs and stool was measured by a Gluspecy test (G test) using factor G, which specifically reacts with (1-->3)-beta-D-glucan. In small intestine and lung, large amounts of factor G-activating substance were observed and identified as (1-->3)-beta-D-glucan by a digestion study using end-(1-->3)-beta-D-glucanase. However, only very small amounts of (1-->3)-beta-D-glucan were found in the kidney, spleen, vena cava, aorta, thymus, heart and liver. In serum and plasma, no (1-->3)-beta-D-glucan was observed. On the other hand, extremely large amounts of (1-->3)-beta-D-glucan were found in stool. Minute amounts of (1-->3)-beta-D-glucan were observed in a variety organs except for the small intestine and lung. High levels of (1-->3)-beta-D-glucan found in the small intestine might be traced to contamination by stool in the small intestine, and such levels in the lung might derive from macrophages which have trapped (1-->3)-beta-D-glucan in the air.