Table 1.

Summary of defects in insulin and PDGF-stimulated signal transduction and GLUT4 translocation (for cell culture models) or 2DOG uptake (for animal model). Down arrows indicate the severity of defect for each variable and tilde represents the absence of a defect.

	IRS-1 Defect		p-Akt		P-TBC1D4		GLUT4/2-DOG
	pY	Expression	Insulin	PDGF	Insulin	PDGF	Insulin	PDGF	Primary Defect
Glucose Oxidase	∼	∼	∼	∼	↓↓	↓↓	↓↓	↓↓	IRS Independent
Chronic Insulin	∼	↓↓	↓↓	∼	∼	∼	↓↓	↓	IRS
TNFα	↓↓	↓↓	↓↓	∼	∼	∼	↓↓	↓↓	IRS + IRS Ind.
Dexamethasone	∼	↓↓	↓↓	↓↓	∼	∼	↓↓	↓↓	IRS + IRS Ind.
Palmitate	∼	∼	∼	∼	∼	∼	↓↓	↓↓	IRS Independent
17d HFD	∼	∼	∼	∼	∼	∼	↓↓	↓↓	IRS Independent