Effects of LPS injection on the hypothalamic and testicular mRNA expression levels of reproductive factors in male rats.

OBJECTIVES In the hypothalamus, kisspeptin and RFamide-related peptide (RFRP) regulate gonadotropin-releasing hormone expression. Kisspeptin and RFRP are also found in the testes and might play roles in steroidogenesis and spermatogenesis. DESIGN AND RESULTS The present study demonstrated that the hypothalamic mRNA expression level of the kisspeptin receptor was decreased by the injection of lipopolysaccharide (LPS) (500 μg/kg) in male rats, and it was suggested that such changes might contribute to reductions in serum luteinizing hormone levels. Contrary to our expectations, hypothalamic RFRP and testicular GPR147 (the RFRP receptor) mRNA expression were also decreased by LPS injection. CONCLUSIONS We speculate that changes in hypothalamic RFRP expression might represent a protective response aimed at attenuating LPS-induced anorectic responses.