Fig. 3. Northern blot of sbAQP expression. (Ai) sbAQP transcripts were expressed in the gastrointestinal tract, where it was most abundant in the hind-gut and rectum, with lower levels detected in the mid-gut. Two transcripts of 2 kb and 1.6 kb were identified in the gastrointestinal tract. A single 2 kb transcript was detected in the kidney. (Aii) The results of northern blot hybridisation with ß-actin. (B) From the semi-quantitative analysis of sbAQP expression (Ai) relative to that of ß-actin (Aii), the hind-gut and kidney were the tissues with the highest expression of sbAQP followed by the rectum and mid-gut. Hatched bars, 2 kb transcript; open bars, 1.6 kb transcript.