Interleukin-1 Directly Stimulates the Release of Corticotrophin Releasing Factor from Rat Hypothalamus

While interleukin-1 (IL-1), a monocyte-derived polypeptide, clearly stimulates the hypothalamo-pituitary-adrenal (HPA) axis, its precise site of action is controversial. In these studies, the possibility of a hypothalamic and/or a pituitary site of action was investigated in vitro, using incubated rat hypothalami and perifused dispersed pituitary cells. Both forms of IL-1, IL-1α and IL-1β, produced a dose-dependent stimulation of CRF-41 release from incubated rat hypothalami in the dose range of 1–100 U/ml (p