Regulation of lamellar body acidic glycerophospholipid biosynthesis in fetal rabbit lung in organ culture.

To study the regulation of lamellar body acidic glycerophospholipid biosynthesis, fetal rabbit lung tissue obtained on day 23 of gestation was maintained in vitro. Tissues were cultured in serum-free medium with and without the addition of cortisol, thyroxine or a combination of both hormones. The addition of cortisol plus thyroxine to the medium resulted in the formation of lamellar bodies containing increased amounts of phosphatidylglycerol and decreased amounts of phosphatidylinositol. The addition of myo-inositol to culture medium containing cortisol plus thyroxine suppressed the incorporation of [14C]glycerol into both phosphatidylglycerol and bis(monoacylglycero)phosphate and enhanced the incorporation of [14C]glycerol into phosphatidylinositol. The effect of myo-inositol on the radioactive labeling of these lamellar body acidic glycerophospholipids was rapid, and was half-maximal at myo-inositol concentrations of approximately 0.10 mM.