Localization of ouabain-sensitive, potassium-dependent nitrophenyl phosphatase in the rectal gland of the spiny dogfish, Squalus acanthias.

摘要: Tissue from the digitiform rectal gland of spiny dogfish, Squalus acanthias, was fixed briefly by formaldehyde perfusion and studied for specificity localization p-nitrophenyl phosphatase (NPP'ase) activity. The enzymatic activity K+-dependent (56%) ouabain-sensitive (67% inhibition). electron-dense reaction product (SrPO4) cytochemical (Ernst, 1972b) localized along inner surfaces basolateral membranes secretory cells. It absent mitochondria, nuclei, vesicles, other organelles. luminal surface cells slightly reactive. On basis (1) this pattern sodium transport system, (2) presence extensive intercellular labyrinthine channels (Bulger, 1963) that would facilitate “standing gradients” (Diamond Bossert, 1968), (3) specific distribution energy-providing we conclude concentration electrochemical gradients recorded secreting (Hayslett et al., 1974) are maintained across domains