Expression of Na,K-ATPase β subunit mRNAs in zebrafish tissues. Total RNA was prepared from adult zebrafish and used as template for RT–PCR. Amplification products were analyzed by electrophoresis on a 1% agarose gel. (Gu) gut; (Ey) eye; (Li) liver; (He) heart; (Te) testis; (Br) brain; (WF) whole fish.