title: Correlation of acute with chronic hypoxic pulmonary hypertension in cattle.
abstract: We investigated acute and chronic hypoxic pulmonary pressor responses in two groups of calves, one bred to be susceptible, the other resistant to high-altitude pulmonary hypertension. Twelve 5-mo-old susceptible calves residing at 1,524 m increased their mean pulmonary arterial pressure from 26 +/- 2 (SE) to 55 +/- 4 mmHg during 2 h at a simulated altitude of 4,572 m. In 10 resistant calves pressure increased from 22 +/- 1 to 37 +/- 2 mmHg. Five calves were selected from each group for further study. When 9 mo old, the 5 susceptible calves again showed a greater pressor response to acute hypoxia (27 +/- 1 to 55 +/- 4 mmHg) than did 5 resistant calves (23 +/- 1 to 41 +/- 3 mmHg). When 12 mo old, the 5 susceptible calves also developed a greater increase in pulmonary arterial pressure (21 +/- 2 to 9 +/- 4 mmHg) during 18 days at 4,572 m than did the 5 resistant calves (21 +/- 1 to 64 +/- 4 mmHg). Acute and chronic hypoxic pulmonary pressor responses were highly correlated (r = 0.91; P less than 0.001) indicating that they were probably produced through a common mechanism.
mesh_terms: D000367:Age Factors; D000403:Airway Resistance; D000531:Altitude; D000818:Animals; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000235:genetics*; D006863:Hydrogen-Ion Concentration; D006976:Hypertension, Pulmonary / Q000235:genetics / Q000662:veterinary*; D000860:Hypoxia / Q000150:complications; D010100:Oxygen / Q000097:blood
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen