Upregulation of interleukin-1 receptors in mouse AtT-20 pituitary tumor cells following treatment with corticotropin-releasing factor. |
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Authors: | E L Webster D E Tracey E B De Souza |
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Affiliation: | Neurobiology Laboratory, National Institute on Drug Abuse, Baltimore, MD 21224. |
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Abstract: | Treatment of AtT-20 cell cultures with increasing concentrations of rat/human corticotropin-releasing factor (r/hCRF) for 24 h resulted in a dose-dependent 2-3 fold increase in specific 125I-labelled recombinant human IL-1 alpha (125I-IL-1 alpha) binding that was paralleled by a 70-80% decrease in 125I-Tyro-ovine CRF binding. Saturation analysis of 125I-IL-1 alpha binding in control and CRF-treated cultures indicated that CRF produced an increase in the density (Bmax) of IL-1 receptors without altering their affinity (KD). The CRF-induced upregulation of IL-1 receptors appears to be mediated through specific membrane receptors for CRF since the CRF receptor antagonist, alpha-helical oCRF (9-41), blocked the CRF-induced upregulation of IL-1 receptors without producing any effect on 125I-IL-1 alpha binding by itself. In summary, these data demonstrate complex interactions between CRF and IL-1 at the pituitary level and identify potential novel mechanisms for cytokines to alter neuroendocrine function. |
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