Effects of gonadectomy on indomethacin-induced ulceration and peptic activity in rats. 
Castration in rats caused a reduction in the degree of ulceration produced by indomethacin.  Compared with the normal intact male rats, the value of the castrated rats was highly significant (18.42 +/- 0.22 compared with 9.58 +/- 0.17) (P less than 0.01).  However, the normal intact male rats had a greater degree of ulceration than the female rats at the pro-oestrous (2.33 +/- 0.13) or oestrous (2.97 +/- 0.12) phases.  The ovariectomized rats, however, showed no significant reduction (P greater than 0.01) in mean ulcer score when compared with the di-oestrous female rats.  The mean value of peptic activity was very high in ovariectomized rats while it was reduced in intact female rats.  The ovariectomized rats were more prone to ulceration than intact female rats although the susceptibility increased in rats at di-oestrus.