Attachment of PC12 cells to adhesion substratum induces the accumulation of glucose transporters (GLUTs) and stimulates glucose metabolism

The levels of glucose transporters (GLUTs), specifically GLUT3 and GLUT1, increased dramatically in PC12 cells that were cultured on suitable adhesion substrate (poly-l-lysine [PLL]) and induced to differentiate with nerve growth factor (NGF). Closer examination of this response revealed that: (1) cellular attachment to PLL was sufficient to stimulate the increase in GLUT immunoreactivity, and (2) NGF alone was not effective unless the cells were cultured on PLL-treated surfaces. The response to PLL was detected as early as 4 hr after plating the cells and peaked within 24-48 hr. Other adhesion substrata, such as collagen and poly-l-ornithine, evoked a similar response, although the latter polymer was far less effective. The increase in GLUTs appeared to result from an accumulation of existing transporters because this response was not blocked by inhibiting protein synthesis. Cellular adhesion to PLL was also accompanied by a rapid activation of glucose metabolism. Thus, specific recognition of the adhesion substratum not only provides a context for cell attachment, but also elicits important functional changes in GLUT activity.