Binding and biological effects of insulin, insulin analogues and insulin-like growth factors in rat aortic smooth muscle cells. Comparison of maximal growth promoting activities.
Binding and growth promoting effects of insulin, insulin analogues modified in the B chain, proinsulin, insulin-like growth factor-I and -II were studied in cultured rat aortic smooth muscle cells. Specific binding of 125I-insulin was 0.9 +/- 0.2% of total 125I-insulin added, and the IC50-value was estimated to 8.9 pmol/l. The insulin analogue B10 Asp tended to be more potent than insulin in displacing 125I-insulin, B28 Asp was equipotent, B9 Asp/B27 Glu was approximately 100 times less potent and insulin-like growth factor-I more than 1000 times less potent than insulin. Specific binding of 125I-insulin-like growth factor-I after 4 h incubation at 10 degrees C was five times higher than the specific binding of insulin (4.4 +/- 0.4% of total 125I-insulin-like growth factor-I added), and the IC50-value was 0.3 nmol/l. Insulin was approximately 500 times less potent than insulin-like growth factor-I in displacing 125I-insulin-like growth factor-I. The insulin analogue B10 Asp was slightly more potent and analogue B28 Asp was equipotent with insulin. Analogue B9 Asp/B27 Glu was ten times less potent and proinsulin was more than ten times less potent than insulin. The order of potency was similar for 3H-thymidine incorporation into DNA: insulin-like growth factor-I greater than B10 Asp greater than insulin-like growth factor-II greater than insulin greater than or equal to B28 Asp greater than B9 Asp/B27 Glu greater than proinsulin. The maximal effect of insulin-like growth factor-I on 3H-thymidine incorporation was 71 +/- 16% higher than the maximal effect of insulin.(ABSTRACT TRUNCATED AT 250 WORDS)
Bornfeldt
K E
KE
Department of Pharmacology, Faculty of Health Sciences, Linköping University, Sweden.
Gidlöf
R A
RA
Wasteson
A
A
Lake
M
M
Skottner
A
A
Arnqvist
H J
HJ
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D001345:Autoradiography; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects*; D002478:Cells, Cultured; D004261:DNA Replication / Q000187:drug effects*; D007328:Insulin / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D008940:Mitotic Index; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011972:Receptor, Insulin / Q000187:drug effects / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
D002352:Carrier Proteins; D007328:Insulin; D018969:Insulin-Like Growth Factor Binding Proteins; D011994:Recombinant Proteins; D014316:Tritium; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D011972:Receptor, Insulin; D013936:Thymidine