Polarized expression of Na+/H+ exchange activity in LLC-PK1/PKE20 cells: II. Hormonal regulation
| العنوان: | Polarized expression of Na+/H+ exchange activity in LLC-PK1/PKE20 cells: II. Hormonal regulation |
|---|---|
| المؤلفون: | Heini Murer, Valeria Casavola, Corinna Helmle Kolb, Stephan J. Reshkin |
| المصدر: | Pfl�gers Archiv European Journal of Physiology. 420:282-289 |
| بيانات النشر: | Springer Science and Business Media LLC, 1992. |
| سنة النشر: | 1992 |
| مصطلحات موضوعية: | Calcitonin, Receptors, Vasopressin, medicine.medical_specialty, Sodium-Hydrogen Exchangers, Swine, Vasopressins, Physiology, Clinical Biochemistry, Receptors, Cell Surface, Cell Line, chemistry.chemical_compound, Physiology (medical), Internal medicine, medicine, Animals, Protein kinase C, Epithelial polarity, Receptors, Angiotensin, Forskolin, Cell Membrane, Inositol trisphosphate, Receptors, Calcitonin, Apical membrane, Enzyme Activation, Sodium–hydrogen antiporter, Endocrinology, chemistry, Type C Phospholipases, Phorbol, Carrier Proteins, Protein Kinases, Adenylyl Cyclases |
| الوصف: | LLC-PK1/PKE20 cells (a continuous epithelial cell line) has two different Na/H exchange activities: Na/H-1 located in the basolateral membrane and Na/H-2 located in the apical membrane [Casavola et al. (1989) Biochem Biophys Res Commun 165:833–837; Haggerty et al. (1988) Proc Natl Acad Sci USA 86:6797–6801]. In the present report we have studied hormone regulation of these exchange activities by measuring Na-dependent recovery of pHi from an acid load (by using microspectrofluorometry and 2,7-bis(carboxyethyl)-5,6-carboxyfluorescein) in response to activation of regulatory cascades by either pharmacological agents or by vasopressin or calcitonin. Agents leading to activation of protein kinase A (cAMP-dependent), such as forskolin (10 μM), 8-Br-cAMP (0.25 mM), and isobutylmethylxanthine (0.5 mM), inhibited Na/H-2 and Na/H-1 by an average of 49%. Stimulation of protein kinase C by a phorbol ester (phorbol 12-myristate 13-acetate, TPA, 100 nM) inhibited Na/H-2 (by an average of 48%) and stimulated Na/H-1 (by an average of 38%); these effects of TPA were also observed in the presence of forskolin (100 μM). Addition of either vasopressin (2 μM) or calcitonin (0.3 μM) onto both sides of the monolayer decreased the activity of Na/H-2 by an average of 26.3% and 27.7% respectively, and stimulated the activity of Na/H-1 by an average of 17.4% and 38.7% respectively; exposure of cells to either hormone stimulated production of cAMP and inositol trisphosphate, respectively. Separate hormone additions to either the apical or basolateral cell surface led to effects similar to those produced by simultaneous hormone additions onto both cell surfaces, although the relative response of Na/H exchangers to either agonist is variable. In summary, these results suggest that in LLC-PK 1/PKE20 cells, vasopressin and calcitonin can act via receptor systems coupled either to adenylate cyclase or to phospholipase C. Activation of these receptor systems can lead to inhibition of Na/H-2 and stimulation of Na/H-1. |
| تدمد: | 1432-2013 0031-6768 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::26525242b59e0a1e3781184cf8687034Test https://doi.org/10.1007/bf00374460Test |
| حقوق: | CLOSED |
| رقم الانضمام: | edsair.doi.dedup.....26525242b59e0a1e3781184cf8687034 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14322013 00316768 |
|---|