Hormonal regulation of leptin mRNA expression and preadipocyte recruitment and differentiation in porcine primary cultures of S-V cells.
The hormonal regulation of leptin mRNA expression and the association between leptin expression and adipocyte differentiation were examined in primary cultures of porcine S-V cells with Northern blot and immunocytochemical analysis. Seeding for 3 days with fetal bovine serum (FBS) with varying levels of dexamethasone (Dex) increased levels of leptin mRNA in a dose-dependent manner in parallel with increases in the proportion of preadipocytes (AD-3 positive cells; AD-3, a preadipocyte marker). Six-day treatment with 10 or 850 nM insulin after FBS+Dex treatment resulted in a similar increase in leptin mRNA expression and morphological differentiation. However, significantly lower levels of leptin mRNA and smaller fat cells were observed in cultures treated with 1 nM insulin or 10 nM insulin-like growth factor-I (IGF-I). Dex-induced increases in leptin mRNA levels and AD-3 cell numbers were blocked completely by the addition of transforming growth factor-beta (TGF-beta) to FBS+Dex-treated cultures. However TGF-beta significantly increased fat cell size and leptin mRNA expression when added to ITS (insulin, 850 nM; transferrin, 5 microg/ml; and selenium, 5 microg/mL) treated cultures during the lipid-filling stage. When added with FBS+DEX for the first 3 days, growth hormone (GH) did not influence the Dex-induced increase in AD-3 cells and leptin mRNA expression, but GH reduced leptin mRNA levels when added with insulin for 6 days after FBS+Dex. These results demonstrated that regulation of leptin mRNA expression by Dex, insulin, IGF-I, TGF-beta, and GH may be associated with changes in preadipocyte number and fat cell size.
Chen
X L
XL
Department of Foods and Nutrition, University of Georgia, Athens.
Hausman
D B
DB
Dean
R G
RG
Hausman
G J
GJ
D017667:Adipocytes / Q000166:cytology*; D000818:Animals; D002452:Cell Count; D002454:Cell Differentiation; D048429:Cell Size; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D013006:Growth Hormone / Q000494:pharmacology; D006728:Hormones / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D020738:Leptin; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology; D013552:Swine; D016212:Transforming Growth Factor beta / Q000494:pharmacology
D006728:Hormones; D007328:Insulin; D020738:Leptin; D011506:Proteins; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D007334:Insulin-Like Growth Factor I; D003907:Dexamethasone; D013006:Growth Hormone