Differentiation of 3T3-L1 Cells

• DMEM (4.5 g/L glucose + L-glutamine – sodium pyruvate; Invitrogen catalog # 11965-092)
• FBS (we test several batches from several sources for differentiation and insulin stimulated glucose uptake then order large quantities of that particular lot. Currently we are using Sigma cat# F2442, lot# 072K8403. Aliquot and store in 50 mL tubes at -20)
• NCS (currently we are using Biowhittaker Cambrex cat# 14-416F, lot# 01106776; aliquot in 50 mL tubes and store at -20)
• PSG (100X Invitrogen Cat# 100378-016)
• Insulin (Sigma I-5523). Dissolve in 0.01N Hydrochloric acid as a 1 mg/ml stock. Aliquot into 1.5 mL tubes and store at -20
• Dexamethasone (Sigma D-1756). Dissolve in ethanol as a 2.5 mM stock. Aliquot into 1.5 tubes and store at -20.
• MIX (Sigma I-5879). Dissolve 2.78g/50mL KOH (0.98g/50mL). Aliquot into 1.5 mL tubes and store at -20
• Fibroblast Media (DMEM + 10% NCS + 1X PSG; Sterile filter into new bottle)
• Adipocyte Media (DMEM + 10 % FBS + 1X PSG; Sterile filter into new bottle)
• DMI Media (Adipocyte Media + Insulin (1000X dilution), Dexamethasone (10 000X dilution) and MIX (500X dilution); Sterile filter into new bottle after additions
• Insulin Media (Adipocyte Media + Insulin (1000X dilution); Sterile filter into new bottle after adding insulin)

File:3T3-L1 Adipocyte Differentiation Schematic.png

• Cells can be grown at 37C + 5% CO2, and split 10-20X. Typically healthy fibroblasts will repopulate in 2-3 days after a 10X dilution.
• Split cells when at about 80% confluence. Confluence initiates the differentiation program, so if cells reach confluence, you will need to thaw another DMSO stock and start over. Splitting cells will normally not reverse this
• When splitting cells, wash cells 2x with sterile PBS then add 0.05% trypsin and sit at room temperature for 2-5 min. Be careful not to over-trypsinize cells
• Cells can normally be passaged up to about passage # 25 without problems.
• Plate cells out in whichever format you require your adipocytes in (ie 12 well plates or 15 cm dishes)

• Let cells grow 2-3 days after confluence (typically 8-10 days after a 10X passage)
• Add Differentiation Media I and incubate 3-4 days. Cells should shrink after day 1 then start to round up and by *day 3 should begin to accumulate lipid (the media should change color as well)
• After 3-4 days, add Differentiation Media II and incubate 2-3 days (for a total of 6 days).
• Change media to Adipocyte media and change every 2-3 days. Insulin responsiveness (as measured by glucose uptake) increases to a maximum at about 10 days post-differentiation.
• Good cells should be homogeneous and have >10 fold insulin stimulated glucose uptake.
• If adipocytes need to be trypsinized for replating or electroporation this is best done before the fourth day after changing to Adipocyte media. Use 0.25% trypsin. After that, cells do not trypsinize well.

PMID 16472699