Regulatory peptides in the urinary bladder of two genera of Antarctic teleosts

Somatostatin 14, prolactin, atrial natriuretic peptide, galanin and urotens in II were found using immunohistochemistry in the urinary bladders of the Antarctic fishes Trematomus bernacchii (Nototheniidae) and Chionodraca hama tus (Channichthyidae) caught in the Ross Sea. The urinary bladders of the t wo species showed a different histology in the epithelial layer. In T. bern acchii the epithelium comprises a single type of columnar cells, while in C . hamatus the columnar cells are restricted to the ventral portion of the b ladder, and the dorso-lateral region is lined by cuboidal cells. No differe nce in the intensity of the immunostaining was observed in the two cell typ es; the only variation was a different distribution of the immunoreactions, which were present in the whole cytoplasm in the cuboidal cells and restri cted to the apical and/or basal portion of the columnar cells.