The effects of sex differences and hormonal factors on the weight loss following intrastriatal injections of quinolinic acid (QA) were examined. Male, female or ovariectomized female rats were weighed each day for 30 days following bilateral injections of 150 nmol of QA or vehicle into the striatum. Although all rats injected with QA exhibited an equivalent initial loss of body weight, female lesioned rats rapidly regained weight and did not differ from controls after the first postsurgical day. On the other hand, male lesioned and female ovariectomized lesioned rats exhibited a significant but transient loss of body weight. By 19 days postsurgery all rats had recovered and exhibited comparable body weights. Histological analysis did not reveal any sex-related differences in the extent of striatal pathology following QA. These results suggest that sex and hormonal variables such as estrogen levels play an important role in the regulatory changes following excitotoxic-induced striatal damage.