Increase in the urinary excretion of histamine after SRBC immunization of rats

Abstract

Summary The twenty-four hour urinary excretion of histamine was determined daily in five rats for nine days after sheep red blood cell (SRBC) immunization. Our prior and current studies in rats have shown an increase in splenic and gastric histamine formation by elevated histidine decarboxylase activity after SRBC immunization. The twenty-four urinary excretion of histamine was elevated throughout the period of study with the peak elevation at six days post immunization. These findings after a humoral immune stimulus, as well as prior observations on cellular immunity, suggest the potential value of this noninvasive technic of monitoring urinary histamine in daily estimations of the total body level of histamine formation and release in laboratory and clinical situations in which this type of information may be of value. The increase in the production and release of histamine in immune challenge situations may be an important factor in the increased incidence of gastrointestinal bleeding in patients with renal transplantation, extensive burns with sepsis, and septic shock.