Interleukin-1 Inhibits NMDA-Stimulated GnRH Secretion: Associated Effects on the Release of Hypothalamic Inhibitory Amino Acid Neurotransmitters

Immune system activation is often accompanied by alterations in the reproductive axis. Interleukin-1 (IL-1), a polypeptide cytokine, has been postulated as a chemical messenger between the immune and the neuroendocrine systems. Using superfused hypothalamic fragments explanted from intact male rats, we evaluated the effects of IL-1 (0.5 and 5 nM) on basal and N-methyl-D-aspartate (NMDA)-stimulated release of gonadotropin-releasing hormone (GnRH), and the associated modifications in the output of inhibitory amino acid neurotransmitters involved in the control of GnRH secretion. IL-1 did not modify basal GnRH release, but markedly restrained the stimulatory effect of NMDA on GnRH secretion. γ-Aminobutyric acid, glycine and taurine concentrations significantly increased in the superfusion medium only after pretreatment with the higher dose of IL-1 (p