Heat stress can cause systemic
physiological and biochemical alterations in living organisms. In
reproductive systems, heat stress induces germ cell loss and poor
quality semen. However, until now, little has been known about such
a complex regulation process, particularly in the perspective of metabolism.
In this study, serum, hypothalamus, and epididymis samples derived
from male SD (Sprague–Dawley) rats being exposed to high environmental
temperature (40 °C) 2 h per day for 7 consecutive days were analyzed
using metabonomics strategies based on GC/TOFMS. Differentially expressed
metabolites reveal that the energy metabolism, amino acid neurotransmitters,
and monoamine neurotransmitters pathways are associated with heat
stress, in accordance with changes of the three upstream neuroendocrine
system pathways in the SNS (sympathetic adrenergic system), hypothalamic
pituitary adrenal axis (HPA), and hypothalamic pituitary testis axis
(HPT) axis. Many of these metabolites, especially in the epididymis,
were found to be up-regulated, presumably due to a self-preserving
action to resist the environmental hot irritation to maintain normal
functioning of the male reproductive system.