Effect of Insulin on Proximal Tubules Handling of Glucose: A Systematic Review

Table 1

Glucose transporter protein and mRNA availability in T1D and T2D murine models.

	Results	Protein	mRNA
GLUT1
T1D	Increased	[79–82] (STZ^WK); [86, 87] (STZ^C)	[81–85] (STZ^WK); [86, 88, 89] (STZ^C)
	Similar	[93] (STZ^WK); [67, 91] (STZ^C)	[93] (STZ^WK)
	Reduced		[92] (STZ^WK)
T2D	Increased		[85] (db/db^WK)
	Similar	[90] (GK^C); [90] (JK^C); [90] (HFD^C)	[22] (OLETF^C)
	Reduced		[92] (GK^WK)
GLUT2
T1D	Increased	[26, 79, 87, 90, 96] (STZ); [99] (Alloxan)	[24, 83] (STZ); [84] (Akita); [97] (Alloxan)
	Similar	[91] (STZ)	[85, 91, 92, 93, 98] (STZ); [96] (Akita)
	Reduced	[95] (Alloxan)	[95] (Alloxan)
T2D	Increased	[25] (MG); [94] (Zucker)	[22] (OLETF); [100] (db/db^§)
	Similar	[90] (GK); [90] (JK); [90] (HFD)	[85] (db/db); [92] (GK); [98] (HFD)
SGLT1
T1D	Increased	[80] (STZ)	[83] (STZ); [84] (Akita)
	Similar		[93, 98] (STZ)
	Reduced	[84] (Akita); [103] (STZ)	[85, 92] (STZ)
T2D	Increased	[90] (GK); [90] (JF); [103] (db/db); [105] (HFD^#)	[104] (OB/OB); [100] (db/db^§); [22] (OLETF); [106] (Zucker); [92] (GK)
	Similar	[100] (db/db^§)	[98] (HFD)
SGLT2
T1D	Increased	[32, 67, 107, 108, 109], [110]^a (STZ); [84, 85] (Akita); [99] (Alloxan)	[32, 83, 107, 108, 109] (STZ); [112] (Alloxan)
	Similar	[93] (STZ)	[93] (STZ)
	Reduced	[85]^b, [113]^a,c (STZ)	[85]^b, [98] (STZ)
T2D	Increased	[90] (JF); [111] (db/db); [94] (Zucker)	[85] (db/db); [100] (db/db^§); [22] (OLETF); [106] (Zucker); [104] (OB/OB)
	Similar	[100] (db/db^§); [105] (HFD^#)
	Reduced		[98] (HFD)

Results were compared to the corresponding controls; numbers are references; the study model is inside the parentheses. Results for GLUT1 were specified for whole kidney (WK) or cortex (C) due to the different availability of GLUT1 in distinct nephron sites, while GLUT2, SGLT1, and SGLT2 are available only at proximal tubules level. ^aShort-duration diabetes. ^bInitially reduced followed by a partial recovery but maintaining lower levels. ^cProtein activity was also reduced. STZ: streptozotocin model; db/db: leptin receptor mutation model; GK: Goto–Kakizaki diabetic rats; HFD: high-fat diet; OLETF: Otsuka Long-Evans Tokushima Fatty rats; MG: monosodium glutamate treatment. ^§Mix model with insulinopenic and insulin-resistant rats. ^#Insulin resistance without changes in glycaemic levels compared to controls.