INTERLEUKIN-1 STIMULATES CORTICOTROPIN-RELEASING FACTOR GENE-EXPRESSION IN RAT HYPOTHALAMUS

To examine the effect of interleukin-1 (IL-1) on CRF and POMC gene expression, recombinant human IL-lα and -β were ip injected in rats. The plasma ACTH level showed a dose-related increase at 2 h after the injection of 0.5 and 2 μg IL-lα and -β, and also showed a sustained increase from 1 h until 5 h after the injection of 2 μg of IL-1β. CRF contents in the medial basal hypothalamus and ACTH contents in the anterior pituitary (AP) decreased at 2 h after the injection of 2 Hg of IL-lα and -β, and such decreased levels were maintained until 5 h after the injection of 2 μg of IL-1β. The levels of CRF mRNA in the hypothalamus and POMC mRNA in AP significantly increased 3 h after the injection of 2 μg IL-lα and -β, and these levels were still higher at 5 h after the injection of 2 μg of IL-1β compared with those of the control. There was no significant change in the ACTH content and POMC mRNA levels in the intermediate-posterior pituitary or the hypothalamus or in the CRF contents and CRF mRNA levels in the cerebral cortex. These results indicate that acute administration of IL-lα and -β stimulates gene expression of hypothalamic CRF and CRF release, which causes the stimulation of ACTH release and POMC gene expression in AP. © 1990 by The Endocrine Society.