Oestrone sulphatase activity of the rat uterus in different hormonal states.

Oestrone sulphatase activity was determined in 12,500 g supernatant of rat homogenates. The conditions used were 0.5 mM oestrone sulphate and 30 min incubation at pH 8.0 and 37 degrees C. The enzyme activity in uteri from normal animals was found to be 5.1 +/- 0.7 nmol (mg protein)-1 h-1. In ovariectomized and hypophysectomized animals the values were significantly higher, whereas subcutaneous administration of 17 beta-oestradiol to such rats resulted in significantly decreased oestrone sulphatase activities. Progesterone increased the enzyme activity of intact rats. It is concluded that the uterine tissue of rats contains oestrone sulphatase which may be of biological importance and which is inhibited by oestrogen.