Tokyo : A particular class of neuron in the brain has been shown by Japanese researchers to influence the release of hormones that regulate ovarian function, including female follicular development and ovulation.
Scientific Reports published these findings, which may aid in the understanding and treatment of reproductive disorders in both humans and animals.
Gonadotropin-releasing hormone (GnRH) and pituitary follicle-stimulating hormone/luteinizing hormone (LH) are released in response to stimuli that are sensed by kisspeptin neurons in the brain.
Pittaya hormones cause the ovaries to initiate their reproductive processes, which is why this process is crucial for reproduction.
For instance, all mammals, including humans, ovulate and develop follicles.
Kisspeptin neurons in the arcuate nucleus (ARC) sustain regular, rhythmic (pulsatile) secretion of GnRH/LH, which supports normal follicular development and sex steroid production; kisspeptin neurons in the anteroventral periventricular nucleus (AVPV) initiate a surge of GnRH/LH, which culminates in ovulation. The fact that the inhibitory chemical dynorphin is produced and reacted to by kisspeptin neurons in the ARC was the emphasis of the study.
“However, the exact role of dynorphin and its receptor in the regulation of kisspeptin neurons was not clearly understood.”
In order to study this, the scientists genetically altered female rats so that only neurons expressing the dynorphin receptor would have the kisspeptin-coding gene Kiss1 deleted.
It was discovered that only three kisspeptin neurons were present in the ARC and fifty percent in the AVPV of the genetically altered rats with deleted Kiss1 in dynorphin receptor-expressing cells. The rats had fewer pups than typical rats, a longer estrous cycle, and a lower ovarian weight, but they were still fertile.
The findings suggest that, because they enable appropriate hormone secretion and ovulation, kisspeptin neurons containing dynorphin receptors are critical for healthy female rat reproduction.
“This is the first report to show that kisspeptin neurons receiving direct input of dynorphin are needed to fully generate the GnRH/LH pulse and surge in female rats,” said Professor Hiroko Tsukamura from Nagoya University.
Professor Tsukamura is excited about the prospect of more studies to understand the molecular mechanism that controls kisspeptin neuronal activity.
“Our findings can help our understanding of the central mechanism underlying reproduction and have applications in the treatment of ovarian disorders in livestock and infertility in humans,” she said.
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