Hormonal regulation of stability of glutamine synthetase mRNA in cultured 3T3-L1 adipocytes.
In 3T3-L1 adipocytes, glutamine synthetase (GS; EC 6.3.1.2) is subject to regulation by dexamethasone, insulin and dibutyryl cyclic AMP (Bt2cAMP). Dexamethasone increases GS-mRNA content and GS-gene transcription, whereas insulin and Bt2cAMP prevent these increases. The effects of these modulators on the control of GS-mRNA stability were investigated. We report here that GS mRNA has a half-life of about 110 min. Bt2cAMP increases GS-mRNA degradation by greater than 2-fold (half-life 50 min), whereas insulin or dexamethasone have little effect on GS-mRNA stability. Down-regulation of GS-gene expression by Bt2cAMP will involve a co-ordinate response at the level of gene transcription and mRNA stability. However, the molecular mechanisms by which insulin and dexamethasone regulate GS-gene expression in cultured adipocytes remains to be elucidated.
Saini
K
K
Laboratory of Cancer Biology, New England Deaconess Hospital, Harvard Medical School, Boston, MA 02115.
Thomas
P
P
Bhandari
B
B
D000273:Adipose Tissue / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology*; D002460:Cell Line; D000242:Cyclic AMP / Q000502:physiology; D003593:Cytoplasm / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D015536:Down-Regulation; D005786:Gene Expression Regulation / Q000187:drug effects; D005974:Glutamate-Ammonia Ligase / Q000235:genetics*; D006207:Half-Life; D007328:Insulin / Q000494:pharmacology*; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000378:metabolism*; D014158:Transcription, Genetic
D007328:Insulin; D012333:RNA, Messenger; D003994:Bucladesine; D003907:Dexamethasone; D000242:Cyclic AMP; D005974:Glutamate-Ammonia Ligase