Growth hormone has dual stage-specific effects on the differentiation of 3T3-L1 preadipocytes.
Reports vary on the role of growth hormone (GH) in adipocyte differentiation. In this study, we showed that GH exerted dual effects depending on the stage of differentiation, using a serum-free culture of 3T3-L1 preadipocytes. GH promoted the differentiation when added to the medium during differentiation-inducing treatment with a hormone cocktail, but apparently suppressed it when added after the treatment. Only the suppressive effect was observed in the presence of 10% fetal bovine serum (FBS). Immunodepletion study showed that GH contributes to the differentiation-promoting activity of FBS. Insulin-like growth factor-1 could not replicate either the stimulative or the suppressive effect of GH. Stimulation of differentiation by GH involved the enhanced expression of mRNA of middle to late adipocyte markers. Among the key regulators of adipogenesis, peroxisome proliferator-activated receptor (PPAR) gamma and CCAAT/enhancer binding protein (C/EBP) alpha, but not C/EBPbeta, were stimulated for mRNA expression by GH added during the treatment with hormone cocktail. The stimulation of adipogenesis by GH was indeed due to the increase in the ratio of differentiated cells, though GH also promoted cell growth.
Tominaga
Sachiko
S
Department of Life Science, Graduate School of Science, Himeji Institute of Technology, Koto, Kamigori, Hyogo 678-1297, Japan.
Morikawa
Minoru
M
Osumi
Takashi
T
D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D000906:Antibodies / Q000378:metabolism; D015415:Biomarkers; D002417:Cattle; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D004305:Dose-Response Relationship, Drug; D013006:Growth Hormone / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D051379:Mice; D044967:Serum / Q000378:metabolism
D000906:Antibodies; D015415:Biomarkers; D016895:Culture Media, Serum-Free; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone