Fig. 1. Adenosine levels in blood serum (open circles) and liver (filled circles) of eelpout (Z. viviparus) during 1 or 3 days of cold exposure. The fish were acclimated to 11°C (t=0) and transferred to 4°C. Data points marked by include samples with adenosine concentration below detection limit. For these samples the detection limit of the method was used for calculations. ^*Significant difference from other time points; significant difference from control (t=0). Values are means ± s.e.m. (N=9–10).