Body weight changes and food and water intakes were studied in CFY male and female rats after kainic acid (KA)-induced destruction of the lateral hypothalamic area (LH) or the ventromedial hypothalamic nucleus (VMH). To minimize the extent of damages, KA was iontophoretically applied by means of glass micropipettes. KA was ejected in 50 or 80 mM concentrations with 5-15 microA current for 5 min. Tip diameter of pipettes varied between 10-20 microns. Lesions were restricted to the LH or VMH. Effects were sex-dependent. LH lesions resulted in hypophagia, hypodipsia and body weight loss only in male rats. On the other hand, only female animals exhibited hyperphagia and weight increase when the VMH was destroyed. The role of sex-dependence in hypothalamic body weight regulation is discussed.