Fig. 3. Summary of effects of amiloride (Am; 10^–4 mol l^–1), acetylcholine (ACh; 10^–3 mol l^–1) and ATP (10^–3 mol l^–1) on short-circuit current (SCC) of tadpole skin cultured for 11–13 days with growth hormone (GH; 1 µg ml^–1) or prolactin (PRL; 1 µg ml^–1), with intact tadpole skin included as control. (A) SCC was measured as the difference between the peak response and the baseline SCC. (B) Time (t) from onset of increase in SCC to peak SCC, measured as indicated. (C) Normalized SCC (%) at 5 min and 20 min after peak response. The SCC measured at 5 min or 20 min after peak was normalized with respect to the maximum response (the difference between peak and baseline SCC being taken as 100%). Values are means ± S.E.M. (no. of experiments is indicated in parentheses).