Testosterone propionate and histamine metabolism in rats

¹ Department of Physiology, University of Malaya, Singapore, State of Singapore

Urinary histamine output has been studied under various experimental conditions in rats. Orchidectomy increased the output of free histamine in rats of the Sprague-Dawley strain but not in rats of the Wistar strain. Subcutaneous administration of testosterone propionate (1 mg/rat) suppressed the output of free histamine in ovariectomized rats but not in normal females, which showed the effect only after repeated administration of this hormone. When exogenous histamine (100 µg) was administered at a constant rate over a 4-hr period, only a minute quantity of administered histamine appeared as free histamine in the urine of male rats. In contrast, 23% of administered histamine appeared as free histamine in the urine of female rats. When repeatedly treated with testosterone, female rats eliminated exogenous histamine more like males. The close relationship between testosterone and histamine metabolism in rats is thus clearly demonstrated.