View source for Differentiation of 3T3-L1 Cells

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==Materials==
*'''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 (28.7μl/50ml) 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 (0.049g/50ml).  Aliquot into 1.5 tubes and store at -20.
*'''MIX''' (Sigma I-5879).  Add 2.78g MIX and 0.98g KOH and bring up to 50 mL.   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 % L1-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]]

==Fibroblast Culture==
*Cells can be grown at 37C + 8% 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 (i.e. 12 well plates or 15 cm dishes)

==Differentiation of Fibroblasts to Adipocytes==
*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.

==Reference==
PMID 16472699
[[ Category:Cell Culture ]]