Insulin resistance in the liver: Deficiency or excess of insulin?

Figures & data

Figure 1. Functional compartmentalization of liver: periportal hepatocytes on left and perivenous hepatocytes on right, with arrow in direction of blood flow.

Table 1A. Zonation of cells, receptors, metabolism and biotransformation in liver. Key: ⁺⁺⁺ predominant localization in periportal or perivenous zone.

	Periportal zone	Perivenous zone
Oxygen gradient^53,54	+++
Cell size^41	15-20 μm	30-40 μm
Kupffer cells^39,40	Phagocytosis	Cytotoxicity
Endothelial cells - Fenestrae^39,40	Larger	Smaller
Stellate cells and Pit cells^39,40	+++
Sympathetic nerves^50	+++
Glucagon receptors^75	+++
Insulin receptors^52		+++
Insulin/glucagon levels^76		+++
Mitochondria and aerobic metabolism^36	+++
Glucose uptake and glycolysis^50		+++
Glucose release: gluconeogenesis^36	+++
Glucose release: glycogenolysis^56	+++
ß-oxidation and ketogenesis^50	+++
Peroxisomal lipid oxidation^70		+++
Triglycerides^59 and VLDL synthesis^83		+++
Cholesterol and bile synthesis^71	+++
Glycogen synthesis from glucose^59		+++
Glycogen synthesis from pyruvate and lactate^50	+++
Uptake of the majority of amino acids^70	+++	+++
Uptake of glutamate and aspartate^70
Uptake of α-ketoglutarate and malate^70	+++	+++
Glutamine synthesis and release^60
Amino acid catabolism and urea synthesis^59	+++
Uric acid synthesis from adenosine^57	+++
Glutation peroxidase and ROS detoxification^50	+++

Table 1B. Zonation of enzyme activity and protein synthesis in liver. Key: ⁺⁺⁺ predominant localization in periportal or perivenous zone.

	Periportal zone	Perivenous zone
Phosphoenolpyruvate carboxykinase^50	+++
Pyruvate carboxykinase^41	+++
Fructose-1,6-biphosphatase^72	+++
Glucose-6-Phosphatase^58	+++
Pyruvate kinase type L^59 and glukokinase^76		+++
Acetyl-CoA carboxylase^83		+++
Suppressor of cytokine signaling 2 (SOCS-2)^68		+++
Glutaminase^60	+++
Glutamine synthetase^48		+++
Succinate dehydrogenase^58	+++
Hydroximethylglutaryl-Coa-reductase^59	+++
Alanine^48 and tyrosine aminotransferase^59	+++
Carbamoyl phosphate synthetase^59	+++
UDP-glucoronosyltransferase^50		+++
Cytocrome P-450^45		+++
Serine dehydratase^61	+++
Fibrinogen and laminin synthesis^50	+++
α2-macroglobulin and conexin 26 synthesis^50	+++
Collagen IV and V synthesis^41	+++
Collagen I, III and VI synthesis^41		+++
α1-antitrypsin and fibronectin synthesis^50		+++
α-fetoprotein and angiotensinogen synthesis^50		+++
Lectin binding^62		+++
Heme synthesis^46		+++
Gene expression of albumin^48		+++
Xenobiotic metabolism^67		+++

Figure 2. Relationship between visceral obesity, insulin resistance, functional compartmentalization and liver steatosis. Visceral adipocytes (VAT), periportal hepatocytes (PPH), perivenous hepatocytes (PVH) and β cells of pancreas (β-CELLS) are represented by squares. Key:↑augmentation; ⊕ stimulation; cardiovascular disease (CV); low-density lipoproteins (LDL); very low density lipoprotein (VLDL); triglyceride (TG).