title: Nongenomic effects of aldosterone on renal protein expressions of pEGFR and pERK1/2 in rat kidney.
abstract: BACKGROUND
  In vitro studies have demonstrated that aldosterone elicits nongenomic actions by enhancing protein expressions of phosphorylated epidermal growth factor receptor (pEGFR) and phosphorylated extracellular signal-regulated kinases 1/2 (pERK1/2). There are no available in vivo investigations regarding this action of aldosterone on renal pEGFR-pERK1/2 protein expressions.
  
  
  METHODS
  Male Wistar rats received normal saline solution, low-dose (LA: 150 μg/kg BW) or high-dose aldosterone (HA: 500 μg/kg BW) by intraperitoneal injection. After 30 min, protein abundances and localizations of renal pEGFR and pERK1/2 were determined by Western blot and immunohistochemistry.
  
  
  RESULTS
  Plasma aldosterone levels were increased in LA and HA groups (p < 0.001). Aldosterone enhanced renal pEGFR and pERK1/2 protein abundances (p < 0.001). HA showed a greater stimulation on pEGFR immunoreactivity than LA in the glomerulus, vasa recta, and thin limb of Henle's loop in the inner medulla area. LA provided more reactivity of pERK1/2 in the thick ascending limb of Henle's loop, outer medullary collecting duct, and proximal straight tubule, whereas HA illustrated more pERK1/2 activation in the glomerulus, peritubular capillary, and inner medulla region.
  
  
  CONCLUSIONS
  This is the first in vivo study which demonstrates that aldosterone, via the nongenomic pathway, could elevate pEGFR and pERK1/2 protein abundances and expressions in the rat kidney. These results indicate that aldosterone induces phosphorylation of EGFR upstream of ERK1/2.
authors.affiliation: Inter-Department of Physiology, Graduate School, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Kittisak
authors.initials: K
authors.lastname: Sinphitukkul
authors.forename: Somchit
authors.initials: S
authors.lastname: Eiam-Ong
authors.forename: Krissanapong
authors.initials: K
authors.lastname: Manotham
authors.forename: Somchai
authors.initials: S
authors.lastname: Eiam-Ong
mesh_terms: D000450:Aldosterone / Q000378:metabolism*; D000818:Animals; D066246:ErbB Receptors / Q000378:metabolism*; D005786:Gene Expression Regulation; D015971:Gene Expression Regulation, Enzymologic; D007150:Immunohistochemistry / Q000379:methods; D007668:Kidney / Q000378:metabolism*; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D008954:Models, Biological; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D000450:Aldosterone; D066246:ErbB Receptors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3