Modulation of epidermal growth factor-induced cell proliferation and receptor binding by insulin in cultured intestinal epithelial cells.
The effect of insulin on EGF-induced cell proliferation and on modulation of EGF receptors was examined in IEC-6 cells in culture. Insulin-induced cell proliferation was not seen until concentration of the hormone reached the microgram (10 micrograms/ml) level, producing an increase in EGF receptor binding affinity (Ka 8.2 +/- .05 x 10(9)M-1 to 1.25 +/- .05 10(10) M-1). In the presence of supraphysiologic concentrations of insulin (10 micrograms/ml), EGF-induced cell proliferation could only be detected at a concentration of 50 ng/ml as opposed to a concentration of 2.0 ng/ml in the absence of insulin. This study suggests that insulin stimulates intestinal crypt cell proliferation only in supraphysiologic concentrations in a manner more characteristic of IGF-I than insulin, while producing enhanced binding of EGF to its receptor as well as an elevated threshold to EGF induced cell proliferation.
Conteas
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CN
Department of Medicine, Wayne State University, Detroit, MI 48201.
McMorrow
B
B
Luk
G D
GD
D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000502:physiology*; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000166:cytology*; D007700:Kinetics
D007328:Insulin; D004815:Epidermal Growth Factor; D066246:ErbB Receptors