Differential regulation of insulin-like growth factor binding protein (IGFBP)-2 mRNA in liver and bone cells by insulin and retinoic acid in vitro.
Isolated cells produce insulin-like growth factors (IGFs) and their binding proteins (IGFBPs). Two distinct cell types were studied with regard to IGFBP-2 expression: (i) rat hepatocytes, which produce IGF I at a high rate and thus regulate its plasma concentration; and (ii) rat osteoblasts, which are targets of IGF I action. IGFBP-2 expression is low in hepatocytes prepared from normal adult rats and high in calvaria cells from newborn rats. Retinoic acid stimulates IGFBP-2 production by liver cells. Insulin suppresses both basal and retinoic acid-induced IGFBP-2 mRNA expression in hepatocytes and has no such effect on osteoblasts. Retinoic acid and insulin regulate IGFBP-2 expression in a tissue-specific manner.
Schmid
C
C
Division of Endocrinology and Metabolism, University Hospital, Zürich, Switzerland.
Schläpfer
I
I
Waldvogel
M
M
Meier
P J
PJ
Schwander
J
J
Böni-Schnetzler
M
M
Zapf
J
J
Froesch
E R
ER
D000818:Animals; D015152:Blotting, Northern; D001842:Bone and Bones / Q000166:cytology / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics*; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D006801:Humans; D015151:Immunoblotting; D007328:Insulin / Q000502:physiology*; D018971:Insulin-Like Growth Factor Binding Protein 2; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014212:Tretinoin / Q000494:pharmacology*
D002352:Carrier Proteins; D007328:Insulin; D018971:Insulin-Like Growth Factor Binding Protein 2; D012333:RNA, Messenger; D014212:Tretinoin