Effects of castration and testosterone replacement on peritoneal histamineconcentration and lung histamine concentration in pubertal male rats

Mast cells, which are: the main source of histamine, are significantly affe cted by sex steroids. The present study was undertaken to determine the eff ects of bilateral castration and testosterone replacement on peritoneal his tamine concentration and lung histamine concentration in pubertal male rats (Wistar strain). Three groups of animals were used in this study: (1) untr eated castrated animals, (2) castrated animals subjected to androgen replac ement by injestion of propionate of testosterone, and (3) intact males as a control group, Castration alone produced a dramatic reduction in peritonea l histamine concentration. In addition, androgen replacement was effective in restoring the histamine concentration to the normal value detected in th e control males (P<0.05, Kruskal-Wallis test). On the other hand, there was no significant variation in the lung histamine concentration between contr ol males, untreated castrated males and castrated males that received andro gen replacement (P<0.05, Kruskal-Wallis test). These results demonstrate fo r the first time that castration markedly reduces the peritoneum histamine concentration in pubertal male rats, and testosterone replacement prevents the decrease. Further, these procedures do not affect lung histamine concen tration, demonstrating that mast cells from different tissues may respond d ifferently to the same biological factors.