Intravenous (i.v.) endotoxin causes fever and induces cortisol and vasopressin release in prepubertal pigs. In order to investigate CNS events associated with these responses, the sequence of the porcine c-fos gene was determined. An oligonucleotide probe complementary to part of the c-fos mRNA sequence was then designed and used to examine the effect of i.v. lipopolysaccharide (LPS: 0.7 µg/kg) on gene expression in the hypothalamus. An increase in c-fos mRNA was detected in the paraventricular and supraoptic nuclei; expression was greater ( P < 0.05) than in normal animals at 30 min, but not at 120, min after LPS injection. These results are consistent with an activational effect of LPS on neuroendocrine pathways involved in the release of anterior and posterior pituitary hormones.
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