The effect of insulin, serum and dexamethasone on mRNA levels for the insulin receptor in the human lymphoblastoic cell line IM-9.
The effect of insulin, serum and dexamethasone on mRNA levels in the insulin receptor in the human lymphoblastoic cell line IM-9 was examined. To this end, mRNA levels were quantitated by Northern blot analysis using a labeled cDNA probe for the insulin receptor. The presence of 0.1 microM dexamethasone in the medium had a strong stimulatory effect on mRNA levels in insulin receptor, suggesting the presence of a glucocorticoid inducible enhancer element near the insulin receptor gene. Also, the nature of the serum had an effect on insulin receptor mRNA levels, as cells maintained in 10% fetal calf serum had insulin receptor mRNA levels that were 40-50% of those found in IM-9 cells maintained in 1% newborn serum. Variations in insulin receptor mRNA levels led in each situation to concordant variations in insulin binding. Insulin levels of up to 1 microM had no effect on hybridizable insulin receptor mRNA levels making an insulin-induced feed-back mechanism on gene expression or mRNA stability unlikely.
Maassen
J A
JA
Krans
H M
HM
Möller
W
W
D001769:Blood; D002460:Cell Line; D004247:DNA / Q000235:genetics; D003907:Dexamethasone / Q000494:pharmacology*; D005312:Fetal Blood; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000378:metabolism*; D011972:Receptor, Insulin / Q000235:genetics*
D007328:Insulin; D012333:RNA, Messenger; D003907:Dexamethasone; D004247:DNA; D011972:Receptor, Insulin