This study was designed to determine the effect of intravenous lipopolysaccharide (LPS) administration on the secretion of interleukin (IL)-1β and IL-1 receptors (IL-1Rs) gene expression in the hypothalamus of anoestrous ewes. Gene expression of IL-1β and its receptors was assayed by the real-time polymerase chain reaction. The expression of IL-1β in the hypothalamus was detected using Western blot. Our results showed that IL-1β mRNA is transcribed in the ovine hypothalamus. Lipopolysaccharide increased (p ≤ 0.01) the IL-1β gene expression in the pre-optic area 2.4-fold, the anterior hypothalamus (AHA) 3.4-fold, the medial basal hypothalamus 3.7-fold and the medial eminence 3.9-fold. The pro-form and mature form of IL-1β protein were found in the hypothalamus after endotoxin injection. In general, the endotoxin also increased more than two times (p ≤ 0.01) the expression of IL-1 receptor type I (IL-1R1) and type II (IL-1R2) genes in the hypothalamus, except the AHA, where the number of IL-1R2 mRNA was extremely low and not sufficient to the quantitative analysis. These results demonstrate that the peripheral immune/inflammatory challenge increases the IL-1β expression in the hypothalamus. This endogenous IL-1β seems to be involved in the modulation of processes which are regulated at the hypothalamic level. One of these processes could be a reproduction.
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