The effect of chronic administration of the non-selective V1 receptor antagonist, dGly[Phaa1,D-tyr(et), Lys, Arg]VP (V1R Ant), or vehicle on adrenalectomy (ADX)-induced changes in the number of cells immunostained for ACTH or deoxybromouridine (BrdU). Rats were subjected to adrenalectomy and implantation of osmotic minipumps (Alza, model 2004) containing the V1 antagonist (230 ng/h/28 days) or vehicle, and BrdU injections for 7 days before sacrifice at day 28. Rats were killed by decapitation and pituitaries fixed for BrdU and ACTH immunohistrochemistry. Bars represent the mean and SE of immunopositive cells counted in pituitary sections of 4 rats per experimental group. *p<0.05 vs. sham; ** p<0.002 vs. sham; *** p<0.001 vs. sham, $p<0.05 vs ADX