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Is there a local IGF-system in human adrenocortical cells?
D l'Allemand1, A Penhoat, W Blum
1Children's Hospital, Charité-Virchow-Klinikum, Humboldt-University, Berlin, Germany. dlalle@ukrv.de
Molecular and Cellular Endocrinology
|August 29, 1998
Summary
Adrenocortical cells secrete Insulin-like Growth Factors (IGFs) and binding proteins (IGFBPs). Adrenocorticotropic hormone (ACTH) stimulates IGF secretion, suggesting a local IGF system regulating steroidogenesis.
Area of Science:
- Endocrinology
- Cell Biology
- Molecular Biology
Background:
- Adrenocorticotropic hormone (ACTH) influences adrenal gland development.
- Insulin-like Growth Factor-I (IGF-I) and IGF-II enhance steroidogenesis and ACTH responsiveness in human adult adrenocortical cells (HAC).
Purpose of the Study:
- To investigate the secretion of IGFs and their binding proteins (IGFBPs) by HAC.
- To determine the long-term regulation of IGFs and IGFBPs by ACTH.
Main Methods:
- Primary cultures of human adult adrenocortical cells (HAC) were used.
- Specific radioimmunoassays (RIAs) and [125I]IGF ligand blot or immunoblot were employed to measure IGFs and IGFBPs.
- Serum-free culture conditions were maintained.
Main Results:
- HAC secrete IGF-I and IGF-II, with secretion significantly stimulated by ACTH.
- At least three IGFBPs were identified, including forms of IGFBP-3, IGFBP-2, and IGFBP-4.
- ACTH did not significantly alter the secretion of any IGFBPs.
- Measured IGF levels are compatible with autocrine or paracrine actions.
Conclusions:
- Human adult adrenocortical cells possess a local IGF system.
- ACTH-stimulated IGF secretion suggests a role in regulating steroidogenesis within the adrenal gland.