Table 2.
Notes on depot- and sex differences in the expression of novel adipokines
| Molecule | Cellular source(s) in adipose tissue |
Auto/paracrine function |
Depot- specific effects on mRNA levels |
Sex-specific effects on circulating or AT mRNA levels |
Effects of obesity |
|---|---|---|---|---|---|
| DPP4 | Adipocytes- COR(+) size; SVF; Mφ |
↓Insulin signaling in adipocytes |
VAT>SAT in obese, |
↑Serum DPP4 ↑DPP4 mRNA in VAT, SAT |
|
| Chemerin | SVF Adipocytes |
Pro-/anti- inflammatory |
SAT mRNA COR(−) serum chemerin |
M & PCOS-F: VAT>SAT F: SAT>VAT Serum chemerin COR(−) serum estradiol |
↑secretion by adipocyte hypertrophy & AT inflammation |
| Lipocalin 2 |
Transports lipophilic substances (retinoids, steroids, arachidonic acid) |
M & PCOS-F: VAT>SAT F: SAT>VAT SAT mRNA COR(−) serum |
↑secretion by AT inflammation Serum levels & relation to insulin sensitivity- varying data |
||
| Gpc4 | Adipocytes Less by SVF |
↑Insulin signaling ↑Adipocyte differentiation |
SAT>VAT in lean |
Serum Gpc4: F: ↑ continuously with ↑BMI M: ↑ from normal weight, to overweight ↓ in obese |
↑VAT, COR(+) BMI, WHR ↓SAT, COR(−) BMI, WHR Serum Gpc4: COR(+) BMI, IR |
| Omentin | SVF | ↑glucose uptake by adipocytes Anti-inflammatory |
VAT>SAT | AT mRNA: F=M Serum omentin COR(−) serum testorsterone |
↓Circulating & gluteal mRNA Serum omentin: COR(−) MetS |
| SFRPs | SAT explant secretes SFRP1,−2,−4 |
↑ adipogenesis SFRP1: antiinflammatory, ↑adiponectin SFRP2–4: inverse to SFRP1 |
Circulating SFRP5 levels: F>M |
SFRP1 mRNA: ↓SAT, ↔VAT SFRP2–4 mRNA: ↑SAT, ↑↑ in VAT Serum SFRP5: varying data |
|
| Vaspin | Adipocytes Precursors SVF |
↑Glucose uptake by adipocytes Anti-inflammatory ↑Adiponectin |
VAT: COR(+) BF SAT: COR(+) IR & WHR |
AT mRNA: F=M, Serum vaspin: F>M |
No mRNA in AT in lean; ↑compensatory with ↑BF, IR |
Abbreviations: DPP4, dipeptidyl peptidase 4; SV, stroma-vascular; Mφ, macrophages; VAT, visceral adipose tissue; SAT, subcutaneous adipose tissue; COR(+)/(−) , positive or negative correlation; PCOS-F, women with polycystic ovarian syndrome; SVF, stromal-vascular fraction; Gpc4, Glypican 4; BMI, body mass index: body weight (kg) : height (cm)2; WHR, waist to hip (circumferences) ratio; F, female(s); M, male(s); TNFα, tumor necrosis factor alpha; SFRPs, a family of five secreted frizzled-related proteins; Wnt, wingless-type ligands; AT, adipose tissue; ↑, increased; ↓, decreased.