Insulin‐responsive glucose transporters are concentrated in a cell surfacederived membrane fraction of 3T3‐L1 adipocytes

FEBS Letters

Lange, Klaus¹  Brandt, Ursula¹ 

[1] Institut für Pharmakologie, Freie Universität Berlin, Thielallee 69-73, D-1000 Berlin 33, FRG

关键词: Glucose transporter;    Adipocyte(3T3-Ll);    Insulin action;    Microvilli;   

DOI  :  10.1016/0014-5793(90)80615-P

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The recently proposed mechanistic concept of a receptor-regulated entrance compartment for hexose transport formed by microvilli on 3T3-L1 adipocytes predicted a preferential localization of glucose transporters in these structures. The cytochalasin B-binding technique was used to determine in basal and insulin-stimulated cells the distribution of glucose transporters between plasma membranes, low density microsomes (LDM) and two cell surface-derived membrane fractions prepared by a hydrodynamic shearing technique. The shearing procedure applied prior to homogenization yielded a low density surface-derived vesicle (LDSV) fraction which contained nearly 60% of the cellular glucose transporters and the total insulin-sensitive transporter pool. The rest of the glucose transporter population was localized within the plasma membrane (5%) and the LDM fraction (37%). Pretreatment of the cells with insulin (20 for 10 min) reduced the transporter content of the LDSV fraction by 40% and increased that of the plasma membrane fraction 4-fold. The transporter containing LDSV fraction was clearly differentiated from the LDM fraction by its low specific galactosyltransferase activity and its insulin-sensitivity. Scanning electron microscopy revealed that the LDSV fraction contained a rather uniform population of spherical vesicles of 100–200 nm in diameter.

【 授权许可】

Unknown