Brain-Derived Neurotrophic Factor Affects mRNA and miRNA Expression of the Appetite Regulating Centre in the Sheep Arcuate Nucleus

The role of QRFP43 in the secretory activity of the gonadotrophic axis in female sheep

In mammals reproduction is regulated by many factors, among others by the peptides belonging to the RFamide peptide family. However, the knowledge concerning on the impact of recently identified member of this family (QRFP43) on the modulation of the gonadotrophic axis activity is still not fully understood and current research results are ambiguous. In the present study we tested the in vivo effect of QRFP43 on the secretory activity of the gonadotrophic axis at the hypothalamic-pituitary level in Polish Merino sheep. The animals (n = 48) were randomly divided into three experimental groups: controls receiving an icv infusion of Ringer-Locke solution, group receiving icv infusion of QRFP43 at 10 μg per day and 50 μg per day. All sheep received four 50 min icv infusions at 30 min intervals, on each of three consecutive days. Hypothalamic and pituitaries were collected and secured for further immunohistochemical and molecular biological analysis. In addition, during the experiment a blood samples have been collected for subsequent RIA determinations. QRFP43 was found to downregulate Kiss mRNA expression in the MBH and reduce the level of IR material in ME. This resulted in a reduction of GnRH IR material in the ME. QRFP43 increased plasma FSH levels while decreasing LH levels. Our findings indicate that QRFP43 inhibits the activity of the gonadotropic axis in the ovine at the level of the hypothalamus and may represent another neuromodulator of reproductive processes in animals.

Brain-derived neurotrophic factor (BDNF) affects the activity of the gonadotrophic axis in sheep

This study aimed to examine the hypothesis that BDNF modulates the activity of the gonadotrophic axis in sheep. Central infusions of BDNF were administered to sexually mature Polish Merino sheep. The sheep were randomly divided into three groups: the control group received intracerebroventricular (ICV) infusions of the vehicle, the BDNF 10 group received ICV infusions of BDNF at 10 μg/480 μL/day, and the BDNF 60 group was infused with BDNF at 60 μg/480 μL/day. A series of four infusions on three consecutive days was performed. Blood samples were collected on days 0 and 3 of the infusions. Immediately after the experiment, all the sheep were slaughtered, and selected structures of the hypothalamus and pituitaries were collected for Real Time RT-qPCR analysis. The collected plasma samples, as well as parts of pituitaries were stored for radioimmunoassay analysis of LH and FSH. Central treatment with exogenous BDNF stimulated GnRH mRNA expression in the preoptic area, as well as GnRH-R mRNA in the pituitary. Furthermore, substantial changes in the KNDy mRNA expression in the mediobasal hypothalamus were observed after the ICV BDNF administration. Additionally, central BDNF infusion caused a decrease in LH concentration and a simultaneous increase in FSH concentration in peripheral blood. Neither pulse amplitude nor pulse frequency for any gonadotrophin was affected in both groups of sheep that received BDNF infusion. Our results revealed that exogenous BDNF affects GnRH and KNDy gene expression and changes in the LH and FSH pituitary cell secretory activities. These findings suggest that BDNF may participate in the mechanism modulating the activity of the gonadotrophic axis at the central level in female sheep.