Regulation of MAPK activity in response to dietary sodium in the rat adrenal gland.
Stimulation of aldosterone biosynthesis by angiotensin II (AII) is thought to be mediated via the PLC, IP3 and intracellular calcium signalling pathway. MAPK (p42/p44) is involved in cell proliferation, and is also activated by AII, but its role in the adrenal response to dietary sodium is unclear. To study the relationship between AII receptor (ATR), MAPK and PKC isoforms, PKCalpha and PKCepsilon, mature Wistar rats were maintained on low or high sodium diets for 1 week. In adrenals from animals on a sodium deplete diet, total ligand binding to both ATR subtypes decreased in the zona glomerulosa (ZG). Under these conditions, active MAPK in the ZG decreased paralleling a decrease in active PKCalpha. In the inner zones (IZ), largely reflecting medullary events, low sodium did not affect MAPK activity. However active PKCalpha decreased. In adrenals from sodium-loaded animals, type 2 ATR (AT2R) binding was reduced in the ZG, while type 1 ATR (AT1R) increased in the IZ. Active MAPK increased in ZG, as did active PKCalpha and PKCepsilon. In IZ, ERK, PKCalpha and PKCepsilon were unchanged. These results suggest that in the ZG and IZ, two different modes of MAPK regulation may exist, utilising different PKC isoforms.
McNeill
H
H
Molecular and Cellular Biology Section, Queen Mary & Westfield College, University of London, UK.
Vinson
G P
GP
D000311:Adrenal Glands / Q000187:drug effects* / Q000378:metabolism*; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D004032:Diet; D005260:Female; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D051571:Protein Kinase C-alpha; D051744:Protein Kinase C-epsilon; D051381:Rats; D017208:Rats, Wistar; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin / Q000378:metabolism; D012964:Sodium / Q000008:administration & dosage* / Q000172:deficiency / Q000494:pharmacology; D015384:Zona Glomerulosa / Q000187:drug effects / Q000378:metabolism
D057911:Angiotensin Receptor Antagonists; D007527:Isoenzymes; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin; D012964:Sodium; C497257:Prkce protein, rat; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D051744:Protein Kinase C-epsilon; D020928:Mitogen-Activated Protein Kinases