GROWTH AND MATURATION OF PRIMARY-CULTURED ADIPOCYTES FROM LEAN AND OBOB MICE/

Stromal vascular cells from epididymal fat pads of lean and obese mice were cultured in a medium (alpha-MEM) containing fetal bovine serum ( FBS) and cell replication followed for 11 days. In both types of cells , confluence occurred at 4-5 days, after which virtual growth arrest o ccurred in lean-mouse cells while replication continued, albeit at a s lower rate in obese-mouse cells. Little or no lipid accumulation or gl ycerol-3-phosphate dehydrogenase (GPDH) activity was observed under th ese conditions. When a differentiation mixture consisting of insulin, corticosterone and isobutylmethylxanthine was added to the serum-conta ining alpha-MEM, a proportion of the lean-mouse cells accumulated trig lycerides and GPDH activity increased significantly, indicating differ entiation. By contrast, little or no differentiation occurred in obese -mouse cells. When cells grown in serum-containing alpha-MEM were tran sferred to a serum-free defined medium at confluence, extensive differ entiation and maturation occurred in lean-mouse cells but not in obese -mouse cells. Similar experiments were conducted in cells isolated fro m the retroperitoneal fat pad. Although the growth pattern was similar to that of epididymal preadipocytes, the retroperitoneal lean- and ob ese-mouse cells differentiated more readily than epididymal cells, as shown by the GPDH specific activity. These data suggest that cells fro m obese mice are resistant to differentiation under conditions that su pport extensive differentiation in lean-mouse cells. (C) 1995 Wiley-Li ss, Inc.