We examined changes in the plasma levels of estradiol (E2), insulin-like growth factor-1 (IGF-1), ACTH, cortisol and catecholamines accompanying various kinds of hypothalamically elicited emotional behaviors in female cats. The emotional behaviors consisting of restlessness, threat and searching-biting (S-B) were elicited intermittently for 6 h by electrical stimulation of the anterior hypothalamus (AH), ventromedial hypothalamus (VMH) and lateral hypothalamus (LH), respectively, in awake and free-moving conditions. The blood was sampled three times immediately before, 1 h after and 6 h after the start of stimulation. The plasma levels of ACTH, cortisol and catecholamines significantly increased in both restlessness and threat behaviors, whereas in the S-B behavior, the ACTH level significantly increased, while the cortisol level showed a slight nonsignificant increase. No changes were observed in the plasma catecholamine levels in the S-B behavior. The plasma E2 level significantly increased in threat behavior after 1 and 6 h of stimulation compared to the prestimulation levels, and the level also increased in comparison to the control group after 1 h. In contrast, the restlessness and S-B behaviors had little or no effect on the E2 level. No significant changes were observed in the plasma levels of IGF-1 in all behavior groups. These findings suggest that various hypothalamically elicited emotional behaviors have differential effects on the plasma E2, but not on the IGF-1 levels. Therefore, E2 and IGF-1 are regulated independently of each other.