Insulin and IGF-1 manifest differential effects in a clonal capillary endothelial cell line.
125I-insulin (10 fmoles) binding plus internalization (BI) to a clonal capillary endothelial (CE) cell line reached to a steady state after 20 min. Acid-washed fraction accounted for nearly half of the total specifically-bound hormone. Dissociation constants (Kd) for insulin-surface receptor in acid-extractable fraction were 0.04 nM (high affinity) and 4.7 nM (low affinity) with a total number of 210,000 high affinity receptors per cell. When 125I-labeled IGF-1 (15 fmoles) was incubated similarly, BI reached only a quasi-equilibrium by 6 min and continued to increase thereafter. 2-Deoxyglucose transport in these cells was stimulated by insulin whereas IGF-1 inhibited its entry.
Brush
J S
JS
Department of Biochemistry and Nutrition, School of Medicine, University of Puerto Rico, San Juan 00936-5067.
Tavárez-Pagán
J J
JJ
Banerjee
D K
DK
D000818:Animals; D001692:Biological Transport / Q000502:physiology; D002196:Capillaries / Q000502:physiology; D002417:Cattle; D002460:Cell Line; D002999:Clone Cells; D003847:Deoxyglucose / Q000378:metabolism; D004730:Endothelium, Vascular / Q000502:physiology*; D007328:Insulin / Q000378:metabolism / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000502:physiology*; D007457:Iodine Radioisotopes; D011972:Receptor, Insulin / Q000378:metabolism
D007328:Insulin; D007457:Iodine Radioisotopes; D007334:Insulin-Like Growth Factor I; D003847:Deoxyglucose; D011972:Receptor, Insulin