Bovine chromaffin cells have insulin-like growth factor-I (IGF-I) receptors: IGF-I enhances catecholamine secretion.
The binding of 125I-insulin-like growth factor-I (125I-IGF-I) to bovine chromaffin cells was measured. Chromaffin cell cultures contained 111,000 +/- 40,000 IGF-I binding sites/cell. These sites bound IGF-I with a KD of 1.1 +/- 0.3 nM and had a much lower affinity for insulin. Cross-linking studies showed that 125I-IGF-I bound to a protein that had an Mr of approximately 125,000, similar to the Mr of the alpha subunit of the IGF-I receptor in other tissues. Cells cultured with IGF-I (10 nM) for 4 days exhibited an almost twofold increase in high K+-evoked catecholamine secretion. Insulin was much less potent than IGF-I in enhancing catecholamine secretion. These data indicate that binding of IGF-I to its receptors on chromaffin cells can modulate the function of these cells.
Dahmer
M K
MK
Department of Pediatrics, University of Chicago, IL 60637.
Perlman
R L
RL
D000311:Adrenal Glands / Q000378:metabolism*; D000818:Animals; D001667:Binding, Competitive; D002395:Catecholamines / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D002838:Chromaffin System / Q000378:metabolism*; D003432:Cross-Linking Reagents; D007328:Insulin / Q000378:metabolism / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000494:pharmacology*; D008970:Molecular Weight; D011188:Potassium / Q000494:pharmacology; D011972:Receptor, Insulin / Q000378:metabolism*; D017451:Receptors, Somatomedin; D013002:Somatomedins / Q000494:pharmacology*
D002395:Catecholamines; D003432:Cross-Linking Reagents; D007328:Insulin; D017451:Receptors, Somatomedin; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D011972:Receptor, Insulin; D011188:Potassium