Kidneys from male rats have twice as much histamine methyltransferase (S-adenosylmethionine:histamine N-methyltransferase, EC 220.127.116.11) activity as kidneys from female rats. Estradiol and testosterone administration to intact males and females respectively does not affect the sex difference in enzyme activity. Castration reduces male activity; the effect of castration can be reversed by a single dose of testosterone. Oophorectomy does not affect female kidney histamine methyltransferase activity. A single injection of testosterone, however, elevates enzyme activity of oophorectomized females. In contrast to rats, the kidneys of female mice contain twice the activity of male kidneys. The sex difference in histamine methyltransferase activity of rat kidneys can explain the sex differences in urinary histamine excretion in rats.
ASJC Scopus subject areas
- Molecular Biology