“…The putative effect of the sex steroids on HIOMT activity is controversial. In female rats, a number of studies reported no effect on HIOMT activity (Yuwiler, 1985(Yuwiler, , 1989Okatani et al, 1998Okatani et al, , 1999, whereas others found various effects Alexander et al, 1970;Houssay and Barcelo, 1972;Nagle et al, 1972;Preslock, 1977). One of the first in vitro studies showed that HIOMT activity in castrated female rats was stimulated (in 2 h) by physiological doses of estradiol, an effect that was abolished in the presence of RNA and protein synthesis inhibitors (Mizobe and Kurokawa, 1976).…”