Corticotropin-releasing factor treatment upregulates interleukin-1 receptors in the mouse pituitary: reversal by dexamethasone.

Intraperitoneal injection of rat/human corticotropin-releasing factor (CRF) (40 micrograms/kg/0.2 ml of saline) resulted in a dramatic increase in specific iodine-125-labeled human interleukin-1 alpha ([125I]IL-1 alpha) binding in the male C57BL/6 mouse pituitary at 2 and 6 h after the injection although it did not affect [125I]IL-1 alpha binding in the mouse hippocampus, spleen and testis at any time after the injection. [125I]IL-1 alpha binding was unchanged at 2 h following dexamethasone (DEX) treatment (1 mg/kg/0.2 ml of 4% ethanol-saline) in the mouse pituitary and the hippocampus. In contrast, DEX inhibited CRF-induced upregulation of IL-1 receptors in the pituitary at 2 h after the injection. These data demonstrate complex interactions between CRF and DEX on IL-1 receptors during stress.