Fig. 5. RT-PCR mRNA expression of RhBG, RhCG1 and RhCG2 in control (0 mmol l^–1 ammonia) and ammonia-exposed (2 mmol l^–1 ammonia) K. marmaratus. For each gene, the following tissues are shown from left to right: brain, eye, gill, gonad, gut, kidney, liver, skeletal muscle and skin. Each gel represents one individual (control N=3, ammonia-exposed N=3). Note RhBG, RhCG1 and RhCG2 are expressed strongly in gill tissue. RhBG expression is low in control tissues except in gill and skin, but higher in many tissues in ammonia-exposed fish. RhCG1 expression in skin is induced with ammonia exposure and RhCG2 expression remains restricted to gill tissues.