Immune activation is often accompanied by profound alterations in neur
ological and endocrine function, such as fever, increased somnolence,
decreased appetite, activation of the hypothalamic-pituitary-adrenal a
xis, and suppression of the hypothalamic-pituitary-gonadal and hypotha
lamic-pituitary-thyroid axes. These well-recognized systemic responses
to injury and infection have been attributed to circulating pro-infla
mmatory cytokines, the best characterized of which is interleukin 1 (I
L-1). Here Emmett Cunningham and Errol De Souza discuss the mechanisms
by which blood-borne IL-1 might affect such changes in the nervous an
d neuroendocrine systems.