Effect of hypoxia on angiotensin II content and its receptor in guinea pig aorta.
OBJECTIVE
To study the effects of hypoxia on the vasoconstrictive response and the angiotensin II (Ang II) content and its receptor.


METHODS
Hypoxia was induced in isolated aorta of guinea pig by gassing N2. The vasoconstrictive response of aorta to Ang II was recorded. Ang II content and its receptor were measured by radioimmuoassay.


RESULTS
Ang 3-3000 nmol L-1 increased the contractile response of aorta. Hypoxia amplified the vasoconstrictive effect of Ang II. The concentration of Ang II were 44 +/- 24 and 50 +/- 17 pg/g wet wt (n = 10), respectively in non-hypoxic and hypoxic aortae. The receptor density in non-hypoxic aorta was 17 +/- 3 fmol mg-1, and that in hypoxia was 33 +/- 5 fmol mg-1 (P < 0.01).


CONCLUSIONS
The enhancement of the vasoconstrictive action of Ang II by hypoxia is due to the increase in the angiotensin receptor density, but not associated with the changes in the Ang II content in hypoxic aorta of guinea pig.
Wang
J F
JF
Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, China.
Dong
H J
HJ
Xiao
W B
WB
D000804:Angiotensin II / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000378:metabolism; D015687:Cell Hypoxia; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D011945:Receptors, Angiotensin / Q000378:metabolism*; D014661:Vasoconstriction / Q000187:drug effects*
D011945:Receptors, Angiotensin; D000804:Angiotensin II