Chronic heat stress (CHS) may trigger systemic biochemical and physiological changes in living organisms.More and more evidence suggests that highly activated under stress conditions neuroendocrine immune network will have a strong and sustained influence the well balanced metabolism of body.In reproductive system, heat stress induces germ cell loss and poor quality semen.However, such a sophisticated metabolic regulatory process has so far been poorly understood, especially from a systemic view.In this study, serum, hypothalamus, and epididymis derived from male sprague-dawley (SD) rats exposed to the elevated ambient temperature (40℃) daily for 2 h for seven consecutive days was analyzed using GC/MS in conjunction with modem multivariate statistical techniques.Metabonomic analysis of this three tissues revealed that sympathetic nervous system (SNS), hypothalamic-pituitary-adrenal axis (HPA) and hypothalamic-pituitary-testis axis (HPT) might be simultaneously affected by chronic heat stress, with Differentially epressed metabolites including metabolites of the energy metabolism, amino acid neurotransmitters, monoamine neurotransmitters etc..Moreover, this metabolites were tightly regulated reproductive function.This study provides important mechanistic insights into the effects of HS-induced reproductive and metabolic dysfunction.