Identification of corticotropin-releasing factor (CRF) target cells and effects of dexamethasone on binding in anterior pituitary using a fluorescent analog of CRF.
A fluorescein-conjugated bioactive analog of corticotropin-releasing factor (CRF) was synthesized and used to label cells that have high affinity CRF-binding sites. Of cultured bovine anterior pituitary cells, 6.1 +/- 0.6% were visible by fluorescence microscopy after incubation with the analog. Fluorescence was eliminated by coincubation with a 200-fold excess of unlabeled CRF. Treatment with dexamethasone (10(-9)-10(-7) M) decreased visible fluorescence in a dose-dependent manner. These results demonstrate the utility of a fluorescent CRF analog for identification of cells with specific CRF-binding sites and suggest that binding of CRF to anterior pituitary cells is altered by glucocorticoids.
D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000818:Animals; D002417:Cattle; D003346:Corticotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000032:analysis*; D003907:Dexamethasone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D051381:Rats
D005456:Fluorescent Dyes; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone