Direct evidence for local generation and release of angiotensin II in human vascular tissue.
A direct measurement of both angiotensins I and II immunoreactive substances was made in the perfusate from isolated human umbilical vein perfused with Krebs-Ringer solution which was free of any component of the renin-angiotensin system. The identity of the immunoreactive peptides was confirmed as angiotensin I and angiotensin II by high-performance liquid chromatography in reference to standard compounds. The rate of release of angiotensins was 41.9 +/- 7.4 and 63.4 +/- 12.0 pg for angiotensins I and II, respectively, during the first perfusion period of 30 min, and it remained stable at least for 3 hours. Angiotensin-converting enzyme inhibitor captopril, added to the perfusion medium (10(-9) to 5 x 10(-6) M), suppressed immunoreactive angiotensin II release in a dose-dependent fashion; the maximal percent inhibition of angiotensin II release evoked by captopril (5 x 10(-6) M) was approximately 56%. These results taken together with the previous observations of presence of essential components of the renin-angiotensin system in vascular tissue provide direct evidence for local generation and subsequent release of angiotensin II in vascular beds of human beings.
Mizuno
K
K
Third Department of Internal Medicine, Fukushima Medical College, Japan.
Tani
M
M
Niimura
S
S
Hashimoto
S
S
Satoh
A
A
Shimamoto
K
K
Inagami
T
T
Fukuchi
S
S
D000803:Angiotensin I / Q000096:biosynthesis / Q000378:metabolism; D000804:Angiotensin II / Q000096:biosynthesis / Q000378:metabolism*; D000809:Angiotensins / Q000302:isolation & purification; D002216:Captopril / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D014471:Umbilical Veins / Q000187:drug effects / Q000378:metabolism
D000809:Angiotensins; D000804:Angiotensin II; D000803:Angiotensin I; D002216:Captopril