Insulin-like growth factor I enhances proenkephalin synthesis and dopamine beta-hydroxylase activity in adrenal chromaffin cells.
Insulin-like growth factor I (IGF-I) increased both the contents of proenkephalin-derived enkephalin-containing peptides and the activity of dopamine beta-hydroxylase in bovine adrenal chromaffin cells. These increases in dopamine beta-hydroxylase and enkephalin-containing peptides continued for at least 8 days. The half-maximal IGF-I concentration for these effects was approximately 1 nM, with maximal effects observed at 10-30 nM. In contrast, insulin was 1000-fold less potent. Pretreatment of chromaffin cells with IGF-I increased the rate of [35S]proenkephalin synthesis 4-fold compared to untreated cells. Total protein synthesis increased only 1.5-fold under these conditions. These results suggest that IGF-I may be a normal regulator of chromaffin cell function.
Wilson
S P
SP
Department of Pharmacology, University of South Carolina School of Medicine, Columbia 29208.
D000313:Adrenal Medulla / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D004299:Dopamine beta-Hydroxylase / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000096:biosynthesis; D004745:Enkephalins / Q000096:biosynthesis*; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000096:biosynthesis*; D011994:Recombinant Proteins / Q000494:pharmacology
D004745:Enkephalins; D007328:Insulin; D011498:Protein Precursors; D011994:Recombinant Proteins; C029992:proenkephalin; D004744:Enkephalin, Methionine; D007334:Insulin-Like Growth Factor I; D004299:Dopamine beta-Hydroxylase