Intrinsic Pituitary Interleukin-1β Is Induced by Bacterial Lipopolysaccharide**

Abstract

Using a specific antiserum recognizing recombinant rat interleukin-1.beta. (IL-1.beta.), immunoreactive material was localized to cytoplasmic granules in anterior pituitary endocrine cells and colocalized with TSH in thyrotropes. Authenticity was established by Northern blot hybridization using a specific rat IL-1.beta. cRNA probe, revealing a 1.8-kilobase mRNA identical to that in the spleen. The marked increase in anterior pituitary IL-1.beta. message after the administration of bacterial lipopolysaccharide, raises the possibility that IL-1.beta. may be involved in paracrine or autocrine regulation of pituitary function during infectious challenge.