Fig. 7. Effect of CsA on calcineurin expression and activity and on response to DDAVP. (A) In an vitro assay (see Materials and Methods), activity of calcineurin was determined in homogenized whole kidneys from control, DDAVP, and CsA+DDAVP mice. ^*P<0.05 compared with wild-type, ^**P<0.05 compared with DDAVP-treated mice. Bar graphs show the mean ± s.e.m. (B) Expression of total CnA was determined in protein from homogenized whole kidneys of control, DDAVP and CsA+DDAVP animals by direct immunoblotting with specific antibodies. Actin was included as a control. Each lane contains protein isolated from one animal. Lanes 1-3, control; lanes 4-6, DDAVP; lanes 7-9: CsA + DDAVP. (C) Urine osmolality was measured in control and CsA-treated animals before and 60 minutes after the subcutaneous injection of DDAVP. Data shown are from eight individual animals per treatment group. ^*P<0.05 (paired t-test). Also shown is the mean osmolality of each group.