FIGURE 1.

Phospholipid composition changes profoundly at onset of 3T3-L1 and OP9 cell differentiation. A, individual PL from 3T3-L1 (A–D) and OP9 cells (E and F) are given as micrograms/dish; B and E, phospholipid values are normalized to cell protein content; C, individual PL are given as % of total PL; D and F, molar PC/PE ratios are given. At the indicated times, nondifferentiated 3T3-L1 cells were harvested, and lipids were extracted. Quantitation of PL was performed by either mass spectrometry (A–D) or gas chromatography (E and F). Values are derived from three independent experiments and represent means ± S.D. in A, B, D, E, and F or mean values in C. confl., confluent preadipocytes; days 5, 9, or 13 (A–D, 3T3-L1) and days 1, 3, or 6 (E and F, OP9) indicate the days after start of adipocyte differentiation.