Synergistic effects of corticotropin and insulin-like growth factor I on corticotropin receptors and corticotropin responsiveness in cultured bovine adrenocortical cells.
Pretreatment of bovine adrenocortical cells with increasing concentrations of insulin-like growth factor I (IGF-I) for 3 days resulted in a dose dependent (ED50 congruent to 5 ng/ml) increment in Corticotropin (ACTH) receptors. Moreover, IGF-I pretreatment potentiated the effects of maximal active concentration of ACTH (10(-9) M) on its own receptors. Whereas ACTH (10(-9) M) or IGF-I (50 ng/ml) alone induced a 3- and 2.5-fold increase respectively in ACTH receptors, there was a 7.5 fold increase in the presence of the two peptides. This synergism between ACTH and IGF-I was also observed for the ACTH-induced cortisol response with an increase of 9-, 3- and 20-fold for cells pretreated with ACTH, IGF-I and the two peptides, respectively. However, the effects of both peptides on ACTH-induced cAMP production was only additive. The present results show that ACTH and IGF-I are potent stimulating factors on bovine adrenal cell differentiated functions and that the effects of both peptides are synergistic.
Penhoat
A
A
INSERM U. 307, Hôpital Debrousse, Lyon, France.
Jaillard
C
C
Saez
J M
JM
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000302:Adrenal Cortex / Q000187:drug effects / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004357:Drug Synergism; D006854:Hydrocortisone / Q000096:biosynthesis; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007700:Kinetics; D018043:Receptors, Corticotropin; D011979:Receptors, Pituitary Hormone / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D013002:Somatomedins / Q000494:pharmacology*
D018043:Receptors, Corticotropin; D011979:Receptors, Pituitary Hormone; D011994:Recombinant Proteins; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D000324:Adrenocorticotropic Hormone; D000242:Cyclic AMP; D015056:1-Methyl-3-isobutylxanthine; D006854:Hydrocortisone