Effects of ventricularly implanted sex steroids on calling and locomotor activity in castrated male Japanese quail.

To clarify the different actions of steroid hormones on calling and locomotor activity, minute pellets of steroid hormones were stereotaxically implanted into the third ventricle of castrated Japanese quail. Testosterone (T) pellets were effective in inducing calling to about 60% of that observed in castrated quail given subcutaneous implants of T. However, implants of 5 alpha-dihydrotestosterone (5 alpha-DHT) were completely ineffective and effectiveness of estradiol-17 beta (E2) was very slight, if any. On the other hand, E2 and T pellets enhanced locomotor activity; E2 was more potent than T, whereas 5 alpha-DHT was again ineffective. Cholesterol pellets had no effects on either behavior. Daily rhythms of calling and locomotor activity were also found in birds given ventricular T implants. These results indicate that T but not E2 is required for induction of calling and that aromatization occurs in the brain to exert enhanced locomotor activity. The results also indicate that changes in circulating T do not influence daily rhythms of calling and locomotor activity.