Adipocyte is a fat cell, that has differentiated and become specialized in the synthesis storage of fat. The adipocyte is important to the body in maintaining proper energy balance, storing calories in the form of lipids, mobilizing energy sources in response to hormonal stimulation, and commanding changes by signal secretions. Under the microscope, the adipocyte appears bloated with triglycerides. The nucleus of the cell is displaced to one side by the fat. The cytoplasm of the cell looks like a thin line surrounding the pool of fat.

Adiponectin (also known as Acrp30, AdipoQ, and GBP28)

• an adipocytokine exclusively expressed and secreted by adipose tissue that regulates lipid and glucose metabolism and plays a key role in body weight regulation and homeostasis. PMID: 16282221
• a novel adipose tissue-specific protein that has structural homology to collagen VIII and X and complement factor C1q, and that circulates in human plasma at high levels. PMID: 12611609

Adipoq

• adipocyte surface marker, involved in adipocyte differentiation in mammals and may play similar roles in chicken. PMID: 16276104

Adipsin

• The mouse adipsin gene encodes a serine protease with complement factor D activity that is expressed during adipocyte differentiation and is deficient in several animal models of obesity. PMID: 2294115
• the adipocyte differentiation-dependent serine protease gene, is a novel serine protease gene whose expression is regulated by a macrophage-derived factor which modulates expression of other adipocyte-specific RNAs. PMID: 3024123

ALK7

• a novel marker specifically expressed during the late phase of adipocyte differentiation. PMID: 16953060

ALBP/aP2 (adipocyte lipid-binding protein)

• belongs to a family of intracellular lipid-binding proteins involved in the transport and storage of lipids, is an early adipocyte marker. PMID: 17077479
• has important effects on insulin resistance, lipid metabolism, and atherosclerosis. PMID: 12377750
• aP2 protein was expressed by lipoblasts in liposarcomas and lipoblastomas and by brown fat cells in hibernomas and normal periadrenal fat. PMID: 10448662

C/EBP alpha/beta (CCAAT-enhancer binding protein)

• members of a family of transcription factors that are integral to adipogenesis. PMID: 15632071
• key adipogenic transcription factors. PMID: 12524424
• Conclusive evidence has already shown that C/EBP alpha regulates terminal adipocyte differentiation, turning on the battery of fat-specific genes required for the synthesis, uptake, and storage of long chain fatty acids. Here we provide evidence that C/EBP delta and C/EBP beta play early catalytic roles in the differentiation pathway, relaying the effects of the hormonal stimulants DEX and MIX in a cascade-like fashion, leading to the activation of the gene encoding C/EBP alpha. PMID: 7531665
• C/EBP and other C/EBP-like proteins play a critical role in regulating the transcription of the fat-specific gene FSP27. PMID: 1339452
• sequences that bind C/EBP and the Fos-Jun complex play major roles in the expression of the aP2 gene during adipocyte differentiation and demonstrate that C/EBP can directly regulate cellular gene expression. PMID: 2511432

DOL54 (a pre-adipocyte marker)

• the gene for the liposarcoma-associated fusion oncoprotein 54 (DOL54) is a target gene of the myxoid liposarcoma and round cell liposarcoma (M-LPS/RC-LPS) oncogene, TLS/FUS-CHOP. The DOL54 gene product is closely associated with adipogenic differentiation. PMID: 12366807, PMID: 15201968

FABP (fatty acid binding protein)

• a cytosolic protein which binds specifically PGE1 but not PGE2, enhances PGE1 and PGE2 binding to isolated adipocyte membranes similarly to albumin. PMID: 2104754
• A-FABP is a small-molecular-mass fatty acid-binding protein that functions by facilitating the intracellular diffusion of fatty acids between cellular compartments as a putative marker of progression. PMID: 15734831
• A-FABP locus is involved in the regulation of intramuscular fat accretion in Duroc pigs. PMID: 9880671
• H-FABP(Heart fatty acid-binding protein), a member of FABP family, plays an essential role in long-chain fatty acid uptake and metabolic homeostasis. PMID: 16800382

FABP4

• a strong positional candidate gene for the FAT1 locus in porcine chromosome 4, is a adipocyte surface marker. PMID: 17032783
• expression occurs not only in mature adipocytes, but has a wider embryonic expression pattern than previously appreciated. PMID: 16952017

GLUT4

• adipocyte specific marker. PMID: 15797240, PMID: 9622342

GPDH (glycerol-3-phosphate dehydrogenase)

• has a central position in lipogenesis in adipose cells. PMID: 17119273
• terminal differentiation marker. PMID: 15737465
• a late marker of preadipocyte differentiation. PMID: 15583048

Leptin

• a well-known adipocyte marker, is synthesized and secreted primarily by adipocytes, and is present in serum in direct proportion to the amount of adipose tissue. PMID: 15968576
• an adipocyte-derived hormone involved in the central control of body weight, energy homeostasis and sexual maturation. PMID: 15234549, PMID: 15138597
• a protein produced by adipocytes which exerts its action on hypothalamus, modifying eating behavior and inhibiting the lust for food consumption. PMID: 9612014

LPIN-1

• LPIN1 expression and suggest a role of LPIN1 in human preadipocyte as well as mature adipocyte function. PMID: 17035674

LPL (lipoprotein lipase)

• involved in the regulation of adipocyte differentiation. PMID: 15922639

Perilipin

• regulates HSL-mediated lipolysis in adipocytes, is a specific adipocyte protein marker. PMID: 16595669, PMID: 12802495
• a major hormonally regulated adipocyte-specific phosphoprotein associated with the periphery of lipid storage droplets. PMID: 2040638

PEPCK-C (Phosphoenolpyruvate carboxykinase)

• the key enzyme in glyceroneogenesis, an important metabolic pathway in adipocytes for reesterification of fatty acids during fasting. PMID: 14739078

PPAR (peroxisome proliferator activated receptor)

• regulate storage and catabolism of fats and carbohydrates. PMID: 15273253
• PPARgamma is possibly a key regulator in the early stages of chicken preadipocyte differentiation. PMID: 15922639
• PPAR gamma is regarded as a "master regulator" of adipocyte differentiation and is abundantly expressed in adipose. PMID: 15777692

Pref-1 (Preadipocyte factor-1)

• found in preadipocytes but is absent in adipocytes, can serve as an excellentmarker for preadipocytes. PMID: 17210639
• an inhibitor of adipocyte differentiation and is synthesized as a plasma membrane protein containing 6 EGF-repeats in the extracellular domain. Pref-1 is highly expressed in 3T3-L1 preadipocytes, but is not detectable in mature fat cells. PMID: 11126233
• an epidermal growth factor-like repeat protein present on the surface of preadipocytes that functions in the maintenance of the preadipose state. pref-1 expression is completely abolished during 3T3-L1 adipocyte differentiation. PMID: 9001251
• an EGF-repeat containing transmembrane protein, is highly expressed in preadipocytes; this expression is totally abolished after differentiation to adipocytes. PMID: 9607168, PMID: 8680480
• a protein containing EGF-like repeats, inhibits adipocyte differentiation. PMID: 8500166

Resistin

• a novel adipocyte-derived cytokine, is involved in the development of insulin resistance and diabetes mellitus. PMID: 15874935
• also known as Adipocyte Secreted Factor (ADSF) and Found in Inflammatory Zone 3 (FIZZ3), is a mouse protein with potential roles in insulin resistance and adipocyte differentiation. The resistin gene is expressed almost exclusively in adipocytes. PMID: 11901161

S-100

• participates in the function of adipocytes. PMID: 2461304
• S-100 protein is expressed from the beginning of lipidogenesis and possibly acts as a factor regulating lipid storage and body fat formation. It can be used as a reliable biochemical marker of human fat cell differentiation and for distinguishing them from the mesenchymal and the fibroblast cells in the human embryonal subcutis. PMID: 11490114

UCP-1/UCP-2 (Uncoupling protein)

• UCP1 is a brown adipocyte-specific mitochondrial uncoupling protein gene marker. PMID: 9802886
• UCP-2 is a mitochondrial protein expressed in adipocytes and has recently been involved in the control of energy dissipation. PMID: 11003590

Other Adipocyte Markers

• Mest/Peg1 imprinted gene enlarges adipocytes and is a marker of adipocyte size. PMID: 15353408