Liver Histamine and Zinc in Guinea Pig Anaphylaxis

Abstract

The anaphylactic histamine release from guinea pig liver under amino-guanidine protection was studied in vivo by injecting antigen into the portal vein. No significant decrease of liver histamine could be observed 2 min after antigen, whereas a significant, though small increase of plasma histamine in the liver blood occurred indicating a histamine release of 1.2% of total liver histamine. When histamine was injected into the portal vein of normal guinea pigs at a dosage about 1.75 times the amount of total liver histamine, 48.8% or even more was retained by the liver. Since, on the basis of our previous studies on heparin release, the liver mast cell disintegration must be considered greater than is suggested by the extent of histamine output, much of the histamine released from the mast cells is probably taken up by the liver cells and metabolized. Zinc which is assumed to link histamine to heparin, was not increased in the liver blood plasma upon challenge with antigen. The guinea pig liver possibly acts as a buffer organ preventing histamine overload of the blood during anaphylaxis. It serves this function by binding hepatic as well as extrahepatic histamine, and in addition, by the heparin-mediated release and activation of liver histaminase which acts both locally and systemically.