The Effect of Growth Hormone on Lipid Accumulation or Maturation in Adipocytes.
BACKGROUND
Adipogenesis of adipocytes includes two stages: initiation and maturation. Growth hormone (GH) secretion is decreased in obese subjects and GH levels are inversely correlated with abdominal fat mass. The effects of growth hormone (GH) on lipids accumulation or maturation of adipocytes remains elusive.


METHODS
In the present study, effect of GH on lipid accumulation in vitro and in vivo was examined. cDNA microarray, quantitative real time-PCR (qPCR) and western blotting was used to analyze the expression of genes related to adipocyte lipid accumulation or degradation in pre- or mature 3T3-F442A adipocytes treated with GH and in epididymal adipose tissue of C57BL/6 mice administrated with GH. Level of adiponectin in supernatants of cultured F442A adipocytes was determined by enzyme-linked immune-sorbent assay.


RESULTS
We found that in 3T3-F442A especially 6 days post initiation of adipogenesis, GH intervention resulted in decreased expression of adipocyte maturation regulators (C/EBPα, PPARγ) and prominent genes related to lipid synthesis such as FAS and FABP, while the expression of UCP1 was markedly enhanced. cDNA microarray analysis and qPCR showed that the expression of SOCS2 and Adipor2 was increased under GH-treatment in mature 3T3-F442A adipocytes. GH treatment increased the mRNA expression of adiponectin and UCP1 in mature adipocytes. The above results were confirmed by in vivo study.


CONCLUSIONS
GH potentially negatively modulates the maturation and accumulation of lipid in adipocytes.
Department of Cell Biology, Shandong University School of Medicine, Jinan, China.
Yuchao
Y
Zhang
Hongsheng
H
Yu
Peng
P
Gao
Jicui
J
Chen
Cong
C
Yu
Chen
C
Zong
Sumei
S
Lu
Xia
X
Li
Xiaoli
X
Ma
Yuantao
Y
Liu
Xiangdong
X
Wang
D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D050156:Adipogenesis / Q000187:drug effects / Q000235:genetics; D052242:Adiponectin / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D064429:Fatty Acid Synthases / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D063990:Gene Ontology; D013006:Growth Hormone / Q000494:pharmacology*; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects* / Q000235:genetics; D008055:Lipids / Q000096:biosynthesis; D008066:Lipolysis / Q000187:drug effects / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D020411:Oligonucleotide Array Sequence Analysis; D047495:PPAR gamma / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D052242:Adiponectin; D022763:CCAAT-Enhancer-Binding Protein-alpha; D008055:Lipids; D047495:PPAR gamma; D012333:RNA, Messenger; D013006:Growth Hormone; D064429:Fatty Acid Synthases