title: Increased EGF binding and EGFR mRNA expression in rat aorta with chronic administration of pressor angiotensin II.
abstract: This study examines the changes in the mRNA expression of epidermal growth factor (EGF), EGF receptor (EGFR), platelet derived growth factor (PDGF-B), and transforming growth factor beta (TGF-beta 1) before and after sustained pressor infusion of angiotensin II (Ang II) for 4 weeks. A threefold increase occurred in the levels of EGFR mRNA (17,240 +/- 827 vs 6403 +/- 1372 units, P less than 0.01) and TGF-beta 1 mRNA (1644 +/- 584 vs 475 +/- 30 units, P less than 0.01) only in the aorta and not in the heart and kidney tissues. This increase in both of the above mRNA transcripts highly correlated (r = 0.96 and 0.92, P less than 0.01) with the elevation of blood pressure. The specific binding of 125I-labeled EGF to aortic membranes also increased (11,429 +/- 728 vs 8630 +/- 420 cpm/mg protein, P less than 0.05) with a parallel increase in the protein tyrosine kinase activity of the membranes indicating that the enhanced EGFR mRNA expression resulted in increased activity of a functional receptor. No significant changes were observed in either EGF mRNA or PDGF-B mRNA levels. These findings suggest that EGFR and TGF-beta 1 participate in the long-term progressive pressor response to Ang II and thus potentially in the progression and the maintenance of chronic hypertension.
authors.affiliation: Department of Medicine, Veterans Administration Medical Center, Sepulveda, California.
authors.forename: M P
authors.initials: MP
authors.lastname: Sambhi
authors.forename: N
authors.initials: N
authors.lastname: Swaminathan
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Rong
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000235:genetics*; D008297:Male; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D000804:Angiotensin II; D004815:Epidermal Growth Factor; D066246:ErbB Receptors