Elasmobranch rectal gland cell: autoradiographic localization of [3H]ouabain-sensitive Na, K-ATPase in rectal gland of dogfish, Squalus acanthias
Specific binding of radiolabeled inhibitor was employed to localize the Na-pump sites (Na,K-ATPase) in rectal gland epithelium, a NaCl- secreting osmoregulatory tissue which is particularly rich in pump sites. Slices of gland tissue from spiny dogfish were incubated in suitable [3H]ouabain-containin...
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ftpubmed:oai:pubmedcentral.nih.gov:2110432 2023-05-15T18:51:07+02:00 Elasmobranch rectal gland cell: autoradiographic localization of [3H]ouabain-sensitive Na, K-ATPase in rectal gland of dogfish, Squalus acanthias 1979-10-01 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2110432 http://www.ncbi.nlm.nih.gov/pubmed/229110 en eng The Rockefeller University Press http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2110432 http://www.ncbi.nlm.nih.gov/pubmed/229110 Articles Text 1979 ftpubmed 2013-09-01T08:46:59Z Specific binding of radiolabeled inhibitor was employed to localize the Na-pump sites (Na,K-ATPase) in rectal gland epithelium, a NaCl- secreting osmoregulatory tissue which is particularly rich in pump sites. Slices of gland tissue from spiny dogfish were incubated in suitable [3H]ouabain-containing media and then prepared for Na,K-ATPase assay, measurement of radiolabel binding, or quantitative freeze-dry autoradiography at the light microscope level. Gross freezing or drying artifacts were excluded by comparison with additional aldehyde-fixed slices. Characterization experiments demonstrated high-affinity binding which correlated with Na,K-ATPase inhibition and half-saturated at approximately 5 microM [3H]ouabain. At this concentration, the normal half-loading time was approximately 1 h and low-affinity binding to nonspecific sites was negligible. Autoradiographs from both 1- and 4-h incubated slices showed approximately 85% of the bound [3H]ouabain to be localized within a 1-micrometer wide boundary region where the highly infolded basal-lateral cell membrane are closest to the mitochondria. These results establish that most of the enormous Na,K- ATPase activity associated with rectal gland epithelium is in the basal- lateral cell membrane facing interstitial fluid and not in the luminal membrane facing secreted fluid. Moreover, distribution along the basal- lateral membrane appears to be nonuniform with a higher density of enzyme sites close to mitochondria. Text spiny dogfish Squalus acanthias PubMed Central (PMC) |
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Articles Elasmobranch rectal gland cell: autoradiographic localization of [3H]ouabain-sensitive Na, K-ATPase in rectal gland of dogfish, Squalus acanthias |
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Specific binding of radiolabeled inhibitor was employed to localize the Na-pump sites (Na,K-ATPase) in rectal gland epithelium, a NaCl- secreting osmoregulatory tissue which is particularly rich in pump sites. Slices of gland tissue from spiny dogfish were incubated in suitable [3H]ouabain-containing media and then prepared for Na,K-ATPase assay, measurement of radiolabel binding, or quantitative freeze-dry autoradiography at the light microscope level. Gross freezing or drying artifacts were excluded by comparison with additional aldehyde-fixed slices. Characterization experiments demonstrated high-affinity binding which correlated with Na,K-ATPase inhibition and half-saturated at approximately 5 microM [3H]ouabain. At this concentration, the normal half-loading time was approximately 1 h and low-affinity binding to nonspecific sites was negligible. Autoradiographs from both 1- and 4-h incubated slices showed approximately 85% of the bound [3H]ouabain to be localized within a 1-micrometer wide boundary region where the highly infolded basal-lateral cell membrane are closest to the mitochondria. These results establish that most of the enormous Na,K- ATPase activity associated with rectal gland epithelium is in the basal- lateral cell membrane facing interstitial fluid and not in the luminal membrane facing secreted fluid. Moreover, distribution along the basal- lateral membrane appears to be nonuniform with a higher density of enzyme sites close to mitochondria. |
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Text |
title |
Elasmobranch rectal gland cell: autoradiographic localization of [3H]ouabain-sensitive Na, K-ATPase in rectal gland of dogfish, Squalus acanthias |
title_short |
Elasmobranch rectal gland cell: autoradiographic localization of [3H]ouabain-sensitive Na, K-ATPase in rectal gland of dogfish, Squalus acanthias |
title_full |
Elasmobranch rectal gland cell: autoradiographic localization of [3H]ouabain-sensitive Na, K-ATPase in rectal gland of dogfish, Squalus acanthias |
title_fullStr |
Elasmobranch rectal gland cell: autoradiographic localization of [3H]ouabain-sensitive Na, K-ATPase in rectal gland of dogfish, Squalus acanthias |
title_full_unstemmed |
Elasmobranch rectal gland cell: autoradiographic localization of [3H]ouabain-sensitive Na, K-ATPase in rectal gland of dogfish, Squalus acanthias |
title_sort |
elasmobranch rectal gland cell: autoradiographic localization of [3h]ouabain-sensitive na, k-atpase in rectal gland of dogfish, squalus acanthias |
publisher |
The Rockefeller University Press |
publishDate |
1979 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2110432 http://www.ncbi.nlm.nih.gov/pubmed/229110 |
genre |
spiny dogfish Squalus acanthias |
genre_facet |
spiny dogfish Squalus acanthias |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2110432 http://www.ncbi.nlm.nih.gov/pubmed/229110 |
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1766244915057000448 |