Interleukin-1β (IL-1β) increases pain behavior and the blood glucose level: Possible involvement of glucocorticoid system

The possible involvement of glucocorticoid system in interleukin-1β (IL-1β)-induced nociception and the blood glucose level was studied in ICR mice. In the first experiment, mice were treated intrathecally (i.t.) with IL-1β (100 pg). Corticotrophin releasing hormone (CRH) mRNA (hypothalamus) and c-Fos mRNA (pituitary gland, spinal cord, and the adrenal gland) levels were measured at 30, 60 and 120 min after IL-1β administration. We found that i.t. injection with IL-1β increased CRH mRNA level in the hypothalamus. The IL-1β administered i.t. elevated c-Fos mRNA levels in the spinal cord, pituitary and adrenal glands. Furthermore, i.t. administration of IL-1β significantly increased the plasma corticosterone level up to 60 min. In addition, the adrenalectomy caused the reductions of the blood glucose level and pain behavior induced by IL-1β injected i.t. in normal and D -glucose-fed groups. Furthermore, intraperitoneal (i.p.) pretreatment with RU486 (100 mg/kg) attenuated the blood glucose level and pain behavior induced by IL-1β administered i.t. in normal and D -glucose-fed groups. Our results suggest that IL-1β administered i.t. increases the blood glucose level and pain behavior via an activation of the glucocorticoid system.