Inhibition of LH action by insulin and insulin-like growth factor I (IGF-I) in trout preovulatory theca layers
Maestro, M.A.; Méndez, E.; Planas, J.V. (2000). Inhibition of LH action by insulin and insulin-like growth factor I (IGF-I) in trout preovulatory theca layers, in: Norberg, B. et al. (Ed.) Proceedings of the 6th International Symposium on the Reproductive Physiology of Fish, Bergen, Norway, July 4-9, 1999. pp. 176 In: Norberg, B. et al. (2000). Proceedings of the 6th International Symposium on the Reproductive Physiology of Fish, Bergen, Norway, July 4-9, 1999. International Symposium on the Reproductive Physiology of Fish, 6. Department of Fisheries and Marine Biology, University of Bergen: Bergen. ISBN 82-7461-048-2. 499 pp., more In: International Symposium on the Reproductive Physiology of Fish. Museo Nacional de Ciencias Naturales. , more |
| Authors | | Top | - Maestro, M.A.
- Méndez, E.
- Planas, J.V.
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| Abstract | In addition to pituitary gonadotropins, insulin and insulin-like growth factor I (IGF-I) are known to have an important regulatory role in the ovary of a number of vertebrates. In a previous study, we correlated the presence of insulin and IGF-I receptors in isolated theca and granulosa cell layers from the coho salmon ovary with specific effects of IGF-I on steroid production. In particular, IGF-I inhibited the LH-stimulated production of testosterone by preovulatory coho salmon theca cell layers. However, the effects of insulin were not examined. We have also previously shown that LH stimulates steroid production in trout preovulatory follicles by activating the cyclic AMP/protein kinase A (cAMP/PKA) signaling pathway. Therefore, the purpose of the present study was to investigate the effects of insulin on theca layer steroidogenesis and to investigate whether insulin and IGF-I inhibit LH-stimulated steroid production in theca cell layers through specific effects along the cAMP/PKA pathway. |
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