Photoperiodic Changes in Both Hypothalamus Neurotransmitters and Circulating Gonadal Steroids Metabolomic Profiles in Relation to Seasonal Reproduction in Male Quail

Abstract

Both hypothalamic neurotransmitters and serum steroid hormones are impacted by photoperiod and have effects on physiology and seasonal reproductive. However, the relationship between circulating gonadal steroids and hypothalamic neurotransmitters underlying different photoperiod is still unclear. To further understand the crosstalk of neurotransmitters and steroids in seasonal reproduction, metabolic changes of 27 neurotransmitters concentrated in hypothalamus tissues and 42 steroids hormones in serum were assessed during two artificial photoperiodic programs. The results showed that photoperiod induce testicular atrophy and recrudescence. In L-to-S groups, significantly decreased levels of testosterone concentration were found in serum (P < 0.001) and increased 11-Dehydrocorticosterone (P < 0.05); Testosterone were almost undetectable at SD_14d. In addition, the hypothalamus exhibited significantly increased arginine and 4-aminobutyric acid (GABA) concentration and decreased serotonin and epinephrine content (P < 0.01 or P < 0.05). Accordingly, serum testosterone and androstenedione became detectable at LD_3d in the S-to-L group and were markedly increase at LD_7d. Furthermore, Serum androstenedione showed a significant increase with long light expose (P < 0.01). Additionally, the hypothalamus exhibited both significantly increased L.Tryptophan and phenylalanine concentration, as well as decreased L-glutamine and L-glutamine.acid content (P < 0.01 or P < 0.05). Serotonin metabolism showed significant differences between L-to-S group and S-to-L group. Furthermore, in the correlation analysis, serum testosterone had a positive correlation with 5-Hydroxyindole-3-acetic acid (5-HIAA), while Androstenedione was significantly negative with L.Tryptophan in L-to-S (P < 0.05). However, in S-to-L group, serum testosterone showed strong negative correlation with both serotonin and 5-HIAA (P < 0.05), but positive correlation with L.Tryptophan (P < 0.01), while Androstenedione was significantly negative correlation with both serotonin (P < 0.05) and L-Glutamine (P < 0.01). Photoperiod also had significant effects on the mRNA expression. We found significant differences in gene expression patterns of both serotonin signaling and steroid biosynthesis, while MAOB, NR5A1, and 3β-HSD showed an opposite tendency between two groups. Taken together, our results revealed that circulating gonadal steroids and hypothalamic neurotransmitters were significantly impact quail’s seasonal reproduction. Circulating gonadal steroids have different effects on neurotransmitter at different photoperiodism, which may coordinately influence the seasonal reproduction of quails.

The dynamic landscape of chromatin accessibility and active regulatory elements in the mediobasal hypothalamus influences the seasonal activation of the reproductive axis in the male quail under long light exposure

“…The experimental animals and the design of the artificial photoperiodism program have been previously described [ 3 ]. Briefly, the artificial photoperiod used to induce the seasonal activation of quails is performed.…”

“…The reproductive cycle of birds is strictly controlled by day length (photoperiod), which results in profound seasonal differences in reproductive behavior when birds are maintained under long- and short-day photoperiods [ 1 ]. In short-daybred Magang geese, initial exposure to long days leads to gonadal inactivity, but switching to short-day conditions drives gonadal activity [ 2 ]; however, in long-daybred quail, maintaining short day inhibits gonadal activity, but changing to long-day conditions activates the reproductive axis and promotes the secretion of testosterone [ 3 ]. The underlying molecular mechanism governing seasonal reproduction in birds is markedly different from that in mammals.…”

The DNA methylation status of the serotonin metabolic pathway associated with reproductive inactivation induced by long-light exposure in Magang geese

“…AB SCIEX QTRAP LC-MS/MS detection platform was used to detect the metabolites in the sample and quantify the content of the neurotransmitter in hypothalamic tissues among the three stages of geese during long light exposure, according to the proposal used in quail [ 18 ]. After whole hypothalamus homogenization, samples were processed for liquid Chromatograph Mass Spectrometer (LS-MS) detection within 24 h. Twenty-three neurotransmitter metabolites (shown in Table S2 ) were measured via Waters ACQUITY UPLC system (Waters, USA).…”

“…How photoperiod impacts on GnRH secretion remain controversial [ 15 – 17 ]. However, the different neuro-mediator systems such as neurotransmitters, vasoactive intestinal peptide (VIP) or thyroid hormone in hypothalamus have been shown to play a role in influencing complex endocrine processes related to photoperiodic regulation of seasonally reproductive activity [ 6 , 18 , 19 ].…”