... levels and urea excretion rates increase markedly, and mRNA expression for the branchial urea transporter mtUT is elevated. Plasma cortisol increases and branchial mRNAs for Rhbg , Rhcg2 and Na + ,K + -ATPase are all upregulated. Enzymatic activity of the latter is activated preferentially by NH 4...

... + ,K + -ATPase were also observed in Xenopus in response to BW acclimation. Most notably, Na + ,K + -ATPase activity in the rectum increased in response to elevated environmental salt concentrations while renal activity decreased. Furthermore, acclimation to BW caused tissue-specific and salinity...

... status,Na + ,K + -ATPase activity and occludin protein expression in the gills, intestine and kidney. Occludin expression altered in response to hydromineral imbalance in a tissue-specific manner suggesting a dynamic role for this TJ protein in the regulation of epithelial permeability in fishes...

... is dependent on an intact ATP-producing system driving basolateral Na + ,K + -ATPase. The persistence of a significant sodium ion influx in the presence of cyanide and iodoacetate is not surprising, given that ATP is still present within the gill ( Table 3 ). However, the resulting ATP levels must...