Hormonal regulation of insulin-like growth factor I secretion by bovine adrenal cells.
The role of insulin-like growth factor I (IGF-I) on the specific function of several steroidogenic cells has been recently reported. Since IGF-I is produced by several tissues, we have investigated whether bovine adrenal cells secrete this peptide. Purification of conditioned medium from adrenal cells incubated with [35S]methionine through affinity chromatography (monoclonal anti-IGF-I antibody), high pressure liquid chromatography, and polyacrylamide gel electrophoresis revealed a single band of similar Mr as pure recombinant IGF-I. Moreover, the purified adrenal-secreted IGF-I displaced bound 125I-IGF-I to its adrenal receptors, and pretreatment of adrenal cells with the purified peptide enhanced the acute corticotropin (ACTH)-induced cAMP production as recombinant IGF-I. The basal secretion of IGF-I (6 +/- 1 ng/48 h/10(6) cells) was stimulated 3-, 4.5-, and 9.5-fold by fibroblast growth factor, angiotensin II (A-II), and ACTH, respectively, but not by growth hormone. The stimulatory effects of A-II and ACTH were dose-dependent (ED50 congruent to 2.5 x 10(-8) and 1.5 x 10(-10) M, respectively), and the effects of both hormones were additive. Glucocorticoids were not the mediators of the effect of the two hormones on IGF-I secretion, since inhibition of their steroidogenic action by aminoglutethimide did not significantly modify IGF-I secretion. An immunoreactive IGF-I material was also secreted by mouse adrenal tumor cell line Y-1, but the stimulatory effect of ACTH was only 2-fold, and there was no effect of A-II. Since bovine adrenal cells contain specific IGF-I receptors and this peptide is required for the maintenance of some adrenal cell-specific function, the present data suggest that IGF-I may act in an autocrine fashion to stimulate adrenal cell differentiation stimulated by ACTH and A-II.
Penhoat
A
A
Inserm U. 307, Hôpital Debrousse, Lyon, France.
Naville
D
D
Jaillard
C
C
Chatelain
P G
PG
Saez
J M
JM
D000311:Adrenal Glands / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D003345:Corticosterone / Q000096:biosynthesis; D003907:Dexamethasone / Q000494:pharmacology; D066298:In Vitro Techniques; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000494:pharmacology; D011869:Radioligand Assay; D011956:Receptors, Cell Surface / Q000502:physiology; D017451:Receptors, Somatomedin; D011994:Recombinant Proteins / Q000494:pharmacology; D013002:Somatomedins / Q000378:metabolism*
D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D011994:Recombinant Proteins; D013002:Somatomedins; D000804:Angiotensin II; D007334:Insulin-Like Growth Factor I; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone