Impaired pulmonary conversion of angiotensin I to angiotensin II in rats exposed to chronic hypoxia
- 31 March 1986
- journal article
- research article
- Published by American Physiological Society in Journal of Applied Physiology
- Vol. 60 (4), 1121-1127
- https://doi.org/10.1152/jappl.1986.60.4.1121
Abstract
The effects of exposing rats to hypoxia at normal atmospheric pressure for periods of 21–24 days on intrapulmonary conversion of angiotensin I (ANG I) to angiotensin II (ANG II) were examined using an isolated rat lung preparation perfused at constant flow. 125I-ANG I (160 fmol) was injected alone and with graded doses (0.1, 1.0, and 100 nmol) of unlabeled ANG I into the pulmonary artery, and the effluent was collected for measurement of ANG I, ANG II, and metabolites. At low doses of injected ANG I (125I-ANG I alone or with 0.1 or 1.0 nmol unlabeled ANG I), the percent conversion of ANG I to ANG II was 67.5 +/- 2.1 (SE), 65.1 +/- 2.0, and 62.5 +/- 1.6 in 21-day hypoxia-exposed animals and 83.8 +/- 2.7, 81.4 +/- 3.9, and 79.6 +/- 2.3 (P less than 0.01) in control rats maintained under normoxic conditions. At the highest dose (100 nmol) of injected ANG I, percent conversion was reduced in both hypoxic and control groups to 46.8 +/- 5.0 and 64.0 +/- 6.0, respectively (P less than 0.05). Mean transit times of labeled material through the pulmonary circulation were not significantly different in hypoxic vs. normoxic lungs at any ANG I load, suggesting that the decreased conversion seen in hypoxic lungs was not related to altered kinetics of substrate exposure. Thus chronic hypoxia is associated with significant inhibition of transpulmonary ANG I conversion that is independent of perfusate flow. We postulate that this phenomenon is due to alterations at the endothelial membrane level.This publication has 21 references indexed in Scilit:
- Kinetics of serotonin uptake in the dog lungJournal of Applied Physiology, 1981
- Properties of angiotensin-converting enzyme in intact cerebral microvessels.Hypertension, 1981
- METABOLISM OF [H-3]BENZOYL-PHENYLALANYL-ALANYL-PROLINE BY PULMONARY ANGIOTENSIN CONVERTING ENZYME INVIVO - EFFECTS OF BRADYKININ, SQ 14225 OR ACUTE-HYPOXIA1981
- Calcium augments hypoxic vasoconstriction in lungs from high-altitude ratsJournal of Applied Physiology, 1980
- Effect of acute hypoxia on the pulmonary conversion of angiotensin I to angiotensin II in dogs.Circulation Research, 1980
- Rat pulmonary circulation after chronic hypoxia: hemodynamic and structural featuresAmerican Journal of Physiology-Heart and Circulatory Physiology, 1979
- Lungs from chronically hypoxic rats have decreased pressor response to acute hypoxiaAmerican Journal of Physiology-Heart and Circulatory Physiology, 1978
- EFFECT OF CONTINUED HYPOXIA ON RAT PULMONARY ARTERIAL CIRCULATION - ULTRASTRUCTURAL-STUDY1978
- CHANGES IN PULMONARY-ARTERIES OF RAT DURING RECOVERY FROM HYPOXIA-INDUCED PULMONARY-HYPERTENSION1977
- PROTEIN MEASUREMENT WITH THE FOLIN PHENOL REAGENTJournal of Biological Chemistry, 1951