AJP - Endocrinology and Metabolism, Vol 249, Issue 1 89-E93, Copyright © 1985 by American Physiological Society
Energy dependence of lung phosphatidylcholine biosynthesis studied with CO hypoxia
A. B. Fisher, C. Dodia and A. Chander
The energy dependence of lung phosphatidylcholine (PC) biosynthesis was
evaluated by measuring incorporation of radiolabeled precursor substrates
by the isolated perfused lung during carbon monoxide (CO)-induced hypoxia.
Ventilation with gases containing 75 or 90% CO (plus 5% O2 and 5% CO2)
resulted in a mean decrease of lung ATP content by 29 and 53%,
respectively, and a significant decrease of [U-14C]glucose incorporation
into free fatty acids and the fatty acyl moiety of lung PC.
[9,10-3H]palmitate incorporation into lung PC was also decreased by hypoxia
but [methyl-14C] choline incorporation was unaffected. For disaturated PC,
incorporation of all three substrates was significantly depressed during CO
ventilation. These results indicate that lung synthesis of PC is inhibited
by alterations of lung energy state. The reactions in lung PC metabolism
that are inhibited by this degree of energy limitation are the de novo
synthesis of fatty acids from glucose, the acylation of exogenous
palmitate, and the remodeling of PC into disaturated PC by the
deacylation-reacylation pathway.
