Table 1.

An overview of tissue-specific fructose metabolism

Importance	Organ	Amount of fructose metabolized	Primary Fructose Transporters	Secondary Fructose Transporters	First Enzyme of Metabolism	Second Enzyme of Metabolism	Third Enzyme of Metabolism	Metabolism Regulated by
Primary sites of metabolism	Intestine	20%	GLUT 5 GLUT 2*	GLUT 7 GLUT 9	KHK-C	ALDOB	TKFC	HIF1a TXNIP ChREBP
	Liver	50–70%	GLUT 2 GLUT8*	GLUT 5 GLUT 9	KHK-C	ALDOB	TKFC	Hypoxia Uric acid ChREBP
	Kidney	20%	GLUT 5 SGLT 5	GLUT 2 SGLT 4	KHK-C	ALDOB	TKFC	HIF1a Uric acid Dehydration
Inducible metabolism	Adipose	0–20%	GLUT 5	-	HK2 KHK-A	ALDOC	-	Hypoxia LXR agonists Glucocorticoid
	Muscle	Inducible	GLUT 5	-	HK2 KHK-A	ALDOA	-	High Fructose Chronic Insulin Tx
Affects organ function	Pancreas	Minimal	GLUT 2	T1R2#	HK1 KHK-A	ALDOB *	-	-
	Brain	Endogenous production	GLUT 5	GLUT 1	HK1 KHK-A	ALDOC	-	Ischemia Microglia stress
Metabolism by other tissues	Testes	Endogenous production	GLUT 5	-	KHK-A	-	TKFC	-
	RBC	Minimal	GLUT 5	-	FN3K	ALDOA	-	-
	Lense	Endogenous production	-	-	FN3K	-	-	-

^“*”denotes less important contribution;

^“-”indicates the data was not found in the literature;

^“#”stands for sweet taste receptor, not a transporter;

GLUT glucose transporter; SGLT5 sodium glucose cotransporter; KHK ketohexokinase; HK hexokinase; FN3K fructosamine 3 kinase; T1R2 taste receptor type 1 member 2; Aldo aldolase; TKFC triokinase; RBC red blood cells; HIF1a hypoxia-inducible factor 1a; TXNIP thioredoxin-interacting protein; ChREBP carbohydrate response element-binding protein; LXR liver X receptor