| Abstract: | Incubation of the adipocytes for 20 hours with insulin or with Bt2cAMP plus the theophylline stimulated adipocyte uptake of AIB and MeAIB but did not stimulate the uptake of glutamine or cycloleucine. MeAIB uptake by both 3T3-L1 preadipocytes and 3T3-C2 cells was relatively unresponsive to insulin. However, MeAIB uptake by 3T3-C2 cells was stimulated by treatment with Bt2cAMP plus theophylline. Incubation of 3T3 adipocytes for 60 min with insulin yielded maximal stimulation of 2-deoxyglucose uptake but no stimulation of the uptake of AIB, MeAIB or glutamine. Responsiveness of transport to Bt2cAMP does not appear to require adipocyte differentiation. By contrast, adipocyte differentiation may be required for the development of the insulin-responsive transport systems. |
