부산대학교 도서관

Bacterial lipopolysaccharide (LPS) and prostaglandins (PG) E2and F2αare putative activators of the hypothalamo-pituitary-adrenal axis. Certain of the biological effects of LPS may be mediated by cytokines such as interleukin-1β (IL-1β), while IL-1β itself may operate via induction of the prostaglandins and/or nerve growth factor (NGF). As IL-1β stimulates the release of corticotrophin-releasing hormone (CRH) from acute rat hypothalamic explants directly, the effects of these substances on the release of CRH in vitrowere investigated in short- and medium-term (20 and 60 min) incubations. The effect of LPS on the release of PGE2and PGF2αfrom these explants, as well as from cortical astrocyte cultures, was also studied.LPS did not modify the release of CRH, PGE2or PGF2αin 20-min incubations. In 60-min incubations, LPS stimulated the release of PGE2, whereas the release of CRH was weakly, but significantly, reduced; PGF2αwas not altered. PGE2significantly stimulated CRH release in the 60-min but not in the 20-min experiments. This effect appeared to be selective for PGE2, since PGF2αdid not modify CRH release, alone or in combination. LPS also selectively released PGE2but not PGF2αfrom cortical astrocyte cultures after 24-h incubation. NGF had no effect on the release of explant CRH, regardless of the length of incubation.It was concluded that neither LPS nor NGF acutely stimulate the hypothalamo-pituitary-adrenal axis by a direct action on hypothalamic CRH, while hypothalamic PGE2may mediate, at least in part, certain of the neuroendocrine responses to LPS.Journal of Endocrinology(1994) 140,103–109