Corticosterone and ambulatory activity in the (ovariectomy and adrenalectomy) rats

The present study was undertaken to investigate the importance of corticosterone (CORT) on the ambulatory activity in the ovariectomized (OVX) rats by employing the automatic apparatus for continuous and direct measurement of ambulation. A significant increase in ambulatory activity was observed in the OVX rats by treatment with estradiol benzoate (E2) (1 microgram/day) for 7 days. Higher dose of E2 (10 micrograms/day) showed a more potent effect on the ambulatory activity. On the other hand, E2 replacement had no effects on ambulatory activity in the OVX + adrenalectomized (ADX) rats. After administration of CORT + E2, ambulatory activity restored to the intact control level in the (OVX + ADX) rats. These data suggest that CORT may be indispensable on the E2-induced increase of ambulatory activity in the (OVX + ADX) rats.