Fig. 2. Expression of the urea transporter (UT) in various tissues of Triakis scyllia as examined by (A) RT-PCR and (B,C) northern blotting. (A) PCR was performed using specific primers for Triakis UT (U) and Triakis GAPDH (G) for three fishes (a-c). Lane 1, brain; 2, gill; 3, kidney; 4, intestine; 5, rectal gland; 6, liver; 7, kidney without reverse transcription. (B,C) 20 µg of poly-A⁺ RNA from the Triakis kidney (lane 1), brain (2), liver (3) and gill (4) were electrophoresed and hybridized with the ³²P-labelled UT cDNA (B) and GAPDH cDNA (C) in high stringent condition.