Biosynthesis of lung lipids from acetoacetate and glucose in the developing rat in vivo.

1. [3-14C]Acetoacetate and [U-14C]glucose administered to rats were readily utilized for synthesis of phospholipids, cholesterol and glycerides in the lung during suckling period. 2. Among all lipids synthesized, phosphatidylcholine accounted for 31-48% from [14C]acetoacetate and 30-46% from [14C]glucose. The synthesized phosphatidylcholine contained predominantly [14C]-labeled palmitate. 3. Glycerol lipids represented 83-92% and 56-68% of total lipids synthesized from [14C]glucose and [14C]acetoacetate, respectively. 4. Glucose is the preferred substrate for glyceride-glycerol, while acetoacetate appears better for fatty acid and cholesterol synthesis.