ASP STIMULATES GLUCOSE-TRANSPORT IN CULTURED HUMAN ADIPOCYTES

OBJECTIVE: The purpose of the present study was to examine the effect of Acylation Stimulating Protein (ASP) on glucose transport in culture d subcutaneous adipocytes. DESIGN AND SUBJECTS: Subcutaneous adipose t issue was obtained from non-obese, healthy females (18-32 y old) under going mammoplasty reduction. Preadipocytes were isolated and different iated into adipocytes. MEASUREMENTS: Following the exposure of preadip ocytes and adipocytes to ASP or insulin, glucose transport was assesse d as [H-3] 2-deoxy glucose uptake. The measurements were normalised pe r total cell protein. RESULTS: ASP increases specific membrane glucose transport in both preadipocytes and adipocytes in a time and concentr ation dependent manner. Stimulation in both cell types is rapid (withi n minutes), reaching a maximal effect between 1 and 4 h. However, afte r 24 h exposure to ASP, there is a downregulation in the response. The ASP response is greater following differentiation of preadipocytes to adipocytes and is compared to that of insulin. Dose response studies demonstrated a five-fold greater sensitivity of adipocytes (half-maxim al concentration of ASP on adipocytes = 0.5 mu M, preadipocytes = 2.3 mu M). CONCLUSION: These results demonstrate that ASP not only stimula tes triglyceride synthesis, but also glucose transport in differentiat ed human adipocytes and is consistent with a physiologically important role for ASP in postprandial energy storage.