Long-term inhibitory effects of somatostatin and insulin-like growth factor 1 on growth hormone release by serum-free primary culture of pituitary cells from European eel (Anguilla anguilla)
| Autor: | Sylvie Dufour, Y.-S. Huang, Karine Rousseau, J Epelbaum, N. Le Belle, J. Marchelidon, B. Vidal |
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| Rok vydání: | 1998 |
| Předmět: |
medicine.medical_specialty
Time Factors Somatotropic cell Endocrinology Diabetes and Metabolism medicine.medical_treatment Culture Media Serum-Free Cellular and Molecular Neuroscience Insulin-like growth factor Endocrinology Desensitization (telecommunications) Internal medicine medicine Animals Insulin-Like Growth Factor I Receptor Cells Cultured Neurons Endocrine and Autonomic Systems Chemistry Growth factor Insulin Anguilla Immunohistochemistry Somatostatin Growth Hormone Pituitary Gland Secretory Rate Hormone |
| Zdroj: | Neuroendocrinology. 67(5) |
| ISSN: | 0028-3835 |
| Popis: | To investigate the ability of hypothalamic and peripheral factors to directly regulate growth hormone (GH) release in a primitive teleost, the European eel (Anguilla anguilla L.), we used primary cultures of dispersed pituitary cells. When cultured for 12 days in a serum-free medium, pituitary cells continuously released large amounts of GH, which exceeded the initial cellular content. Somatotropin-release inhibiting hormone (SRIH-14) dose-dependently inhibited GH release (EC50 0.75 nM) up to a maximal inhibitory effect of 95%. No desensitization of somatotropes to SRIH was observed over the 12 days of culture. Use of receptor subtype-selective SRIH agonists suggests the existence on eel somatotropes of SRIH receptor(s) related to the mammalian sst2/sst3/sst5 class rather than to the sst1/sst4 class. Insulin-like growth factor 1 (IGF1) dose-dependently inhibited GH release (EC50 0.03 nM) up to a maximal inhibitory effect of 85%, without desensitization. IGF1 and IGF2 were equipotent in inhibiting GH release, whereas insulin was 1,000 times less active, suggesting the implication of a receptor related to the mammalian IGF type 1 receptor. These results indicate that eel somatotropes are active in vitro without any specific additional factors, and suggest the existence of a dominant inhibitory control of GH release in vivo. Two potential candidates for this chronic negative regulation are a neurohormone, SRIH and a circulating factor, IGF1. These data underline the early evolutionary origin of the molecular and functional SRIH-GH-IGF1 neuroendocrine axis in vertebrates. |
| Databáze: | OpenAIRE |
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