Effects of female sex hormones on histamine metabolism in guinea-pigs.

Determination of the urinary excretion of histamine and methylhistamine was performed in intact and gonadectomized male and female guinea-pigs. The excretion of methylhistamine varied more than that of histamine both in the same animal and between different animals. The urinary excretion of histamine and methylhistamine reflects fairly well the total histamine turnover in the animal, provided that aminoguanidine is administered to inhibit diamine oxidase activity. There was no sex difference in the excretion of histamine and methylhistamine and gonadectomy did not influence the urinary output. Female sex steroids had little ifany effect upon histamine turnover in the guinea-pig which is in contrast to the situation in rats and mice.