Fig. 6. cG-PDE activity is significantly inhibited by capa-1 peptide. cGK (A) and cG-PDE (B) activities were assayed in tubule preparations from for^R and for^s animals as described, under control and capa-1-stimulated conditions. cGK activity was assessed in the presence of cGMP. Tubules were pre-treated with capa-1 (10^-7 mol l^-1) (Kean et al., 2002) for 10 min, prior to homogenisation and sample preparation. In order to aid comparison, data for both cGK and cG-PDE activity in the presence of capa-1 are expressed as % of untreated activity, mean ± S.E.M. (N=4-6). ^*Statistically significant data between controls (100%) and capa-1-treated samples (P<0.05).