Angiotensin II AT1 receptors and Na+/K+ ATPase in human umbilical vein endothelial cells.
Cultured human umbilical vein endothelial cells (HUVECs) at passage 4 specifically bound 70 +/- 12 fmol [3,5-3H]Tyr4-Ile5-angiotensin (Ang) II/mg protein, with a Kd of 0.9 +/- 0.36 nM. Binding was eliminated in cells preincubated with a monoclonal antibody (6313/G2) raised against the subtype AT1 of the Ang II receptor. Freshly seeded HUVECs were positive for 6313/G2 antibody by immunocytochemistry, and such immunoreactivity was still retained at passage 4. Incubation of HUVECs for 20 min with different concentrations of Ang II provoked a significant increment in Na+/K+ ATPase activity compared with controls, in a dose- and time-dependent manner. Maximal response was obtained with 1000 pM Ang II after 20 min stimulation and resulted in a 2.2-fold increment in Na+/K+ ATPase activity. This stimulation was abolished when cells were incubated with 1000 pM Ang II in the presence of 1 microM of the specific AT1 subtype inhibitor, DuP753. Moreover, preincubation of HUVECs with 6313/G2 or with 1 mM dithiothreitol also inhibited the stimulatory effect of Ang II. These results suggest that the AT1 receptor subtype mediates the Na+/K+ ATPase response to Ang II in these cells.
Muscella
A
A
Dipartimento di Biologia, Università di Lecce, Italy.
Marsigliante
S
S
Carluccio
M A
MA
Vinson
G P
GP
Storelli
C
C
D000804:Angiotensin II / Q000494:pharmacology*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D011945:Receptors, Angiotensin / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D014471:Umbilical Veins; D014741:Video Recording
D011945:Receptors, Angiotensin; D000804:Angiotensin II; D000254:Sodium-Potassium-Exchanging ATPase