Reduction of postprandial lipemia after acute exposure to high altitude hypoxia.
The effects of acute exposure to high altitude hypoxia upon plasma levels of lipids and lipoproteins were studied in 6 healthy subjects observed under strict dietary control. Fasting and postprandial values, first measured at low altitude (< 300 m), were compared to values measured 7 days after transfer by helicopter to the Observatoire Vallot (4350 m) near Mont-Blanc. Plasma levels of catecholamines and thyroid hormones were measured in parallel. Under normoxic conditions, a rise in plasma levels of cholesterol, triglycerides and phospholipids was found 4 hr after the test-meal, whereas circulating norepinephrine fell. Under hypoxic conditions, postprandial effects on lipid parameters disappeared, lipemic responses to the test-meal were dramatically reduced and plasma levels of norepinephrine increased. These effects were accompanied by a fall in triglyceride-rich lipoproteins, generally associated with a slight elevation of HDL-cholesterol, especially the less dense HDL2 fraction. When all results obtained in normoxic and hypoxic conditions were analyzed together, a series of highly significant correlations were found between the magnitude of postprandial lipidemia and various lipid parameters, in particular HDL2-cholesterol which was negatively correlated. These observations strongly suggest that high altitude hypoxia, independent of interfering variables such as exercise training or cold exposure, induced a net stimulation of the lipolysis of plasma triglycerides.
Férézou
J
J
Laboratoire de Physiologie de la Nutrition, Université Paris-Sud, Orsay, France.
Richalet
J P
JP
Sérougne
C
C
Coste
T
T
Wirquin
E
E
Mathé
D
D
D000328:Adult; D000531:Altitude; D002395:Catecholamines / Q000097:blood; D005215:Fasting / Q000097:blood; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000097:blood* / Q000209:etiology; D008055:Lipids / Q000097:blood*; D008074:Lipoproteins / Q000097:blood; D008297:Male; D010865:Pilot Projects; D013963:Thyroid Hormones / Q000097:blood
D002395:Catecholamines; D008055:Lipids; D008074:Lipoproteins; D013963:Thyroid Hormones