Immunofluresence analysis of hapothalamic supraoptic AVP neurons. A: There was no change in number of AVP-positive neurons in control group. B: AVP-immnopositive neurons at the 3 d after hypophysectomy. There was a bit decrease of AVP-positive cells. C, D and E: AVP-positive neurons at the 10 d, 20 d and 30 d respectively. The number of AVP-positive neurons decreased from the 10 d and reached minimum at 20 d and 30 d. F: AVP-positive cell counts. There were 93.2% of AVP-positive neurons survived at the 3 d after hypophysectomy,75.4% at the 10 d, 32.2% at 20 d and 29.2% at 30 d (*, P < 0.01 compared with the control group). The numbers of AVP-immunopositive neurons at 20 d and 30 d were significantly less than that at 10 d but there was no difference between those at the 20 d and 30 d (#, P < 0.01 compared with the 10 d).