title: Effects of ghrelin on the proliferation and differentiation of 3T3-L1 preadipocytes.
abstract: The effects of ghrelin on the proliferation and differentiation of 3T3-L1 preadipocytes and the possible mechanisms were investigated in this study. 3T3-L1 preadipocytes were cultured in vitro and treated with different concentrations of ghrelin. Proliferation of 3T3-L1 preadipocytes was evaluated by MTT method and mRNA levels of c-myc and thymidine kinase were detected by RT-PCR. Morphological changes of 3T3-L1 preadipocytes were observed and cell differentiation was measured by oil red O staining. The mRNA levels of peroxisome proliferator-activated receptor gamma (PPARgamma) and CAAT/enhancer binding protein (C/EBPalpha) in the cells at different differentiation stages were detected by RT-PCR. The results showed that ghrelin at concentrations of 10(-7) to 10(-15) mol/L could significantly promote preadipocyte proliferation (P<0.05), with the most pronounced effect observed at 10(-11) mol/L (P<0.01). Treatment of 3T3-L1 preadipocytes with ghrelin significantly increased the mRNA levels of c-myc and thymidine kinase (P<0.01). Morphological findings demonstrated that the great amount of lipid droplets appeared in the 3T3-L1 preadipocytes treated with ghrelin. Ghrelin could morphologically induce the differentiation of 3T3-L1 preadipocytes into mature adipocytes. Ghrelin significantly increased the mRNA levels of PPARgamma and C/EBPalpha during the differentiation, when compared with control group (P<0.05). The mRNA levels of PPARgamma and C/EBPalpha were obviously up-regulated with the differentiation of preadipocytes after the treatment of ghrelin. There were significant difference in the mRNA levels of PPARgamma and C/EBPalpha on day 2 and day 8 of the differentiation of 3T3-L1 preadipocytes (P<0.01). In conclusion, ghrelin could promote the proliferation and differentiation of 3T3-L1 preadipocytes by increasing the mRNA levels of PPARgamma and C/EBPalpha and therefore enhance the sensitivity of adipocytes against insulin.
authors.affiliation: Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China. liujing821218@sohu.com
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Hanhua
authors.initials: H
authors.lastname: Lin
authors.forename: Peixuan
authors.initials: P
authors.lastname: Cheng
authors.forename: Xiufen
authors.initials: X
authors.lastname: Hu
authors.forename: Huiling
authors.initials: H
authors.lastname: Lu
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000187:drug effects*; D000818:Animals; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D054439:Ghrelin / Q000494:pharmacology*; D051379:Mice; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; D054439:Ghrelin; D047495:PPAR gamma; D012333:RNA, Messenger