Researchers have identified the missing link between stress and infertility. They did this by confirming that a population of nerve cells near the base of the brain can cause infertility when a person is stressed. Specifically, the RFamide-Related Peptide (RFRP) neurons become active in the presence of the stress hormone cortisol to suppress the reproductive system.
Fertility is defined as the capability to conceive and give birth to progeny. Unfortunately, this process goes amiss in 48.5 million couples worldwide in a condition is known as infertility. This distressing problem is diagnosed when a couple cannot conceive after having regular unprotected sex for a set period or when a woman is unable to carry a pregnancy to full-term.
As it stands, there are countless causes of infertility, with many physiological modes of this condition still unknown or unclear. Pursuant to this, the relationship between stress and infertility has been debated for years with infertile couples reporting elevated levels of anxiety and depression. This, in turn, suggests that infertility causes stress, what is still unclear, however, is whether stress causes infertility.
Stress can cause infertility
Now, a study from researchers at the University of Otago proves that stress is indeed capable of causing infertility. The team states they discovered a population of nerve cells near the base of the brain called the RFRP neurons that become active in stressful situations to suppress the reproductive system. The study is published in The Journal of Neuroscience.
Previous studies show that when infertility causes significant distress to couples psychological intervention can decrease this depression whilst increasing pregnancy rates. However, the link between distress and the lack of conception is yet to be realized.
What we know so far is that stress hormones such as cortisol are probably part of the mechanism involved. To add to the confusion, brain cells that control reproduction are unable to respond to cortisol, creating a ‘missing link’ in between the brain and the endocrine-run reproductive system.
A possible answer to this quandary is RFRP neurons that produce RF-Amide Related Peptide 3, a reproductive inhibitory hormone. This is because they have been shown to suppress both puberty and sexual reproduction, and are also activated during stress. The current study investigates whether alterations in RFRP neuronal activity under stress lead to changes in puberty onset, fertility, and stress responses.
Stress affect neurons controlling reproduction
In the present trial transgenic techniques were used to show that when the activity of the RFRP cells is increased, reproductive hormones are suppressed as if the stress hormone cortisol were present. To test this theory the RFRP neurons were silenced and cortisol was introduced into the system to induce stress. Remarkably, the reproductive system continued to function as if the cortisol was never there. Thus, proving that the RFRP neurons are a critical piece of the puzzle in stress-induced suppression of reproduction.
Data findings show that chronic RFRP neuronal activation delayed both the onset of male puberty and female reproductive cycle progression, as well as causing cortisol secretion. Interestingly, collated results show the reaction was most evident in females.
The team states they have now identified that RFRP neurons are indeed the missing link between stress and infertility. In brief, the neurons become active in stressful situations, due to increasing levels of cortisol, causing them to suppress the reproductive system.
A possible treatment for stress-induced infertility
In conclusion, their data leads them to believe they could overcome stress-induced infertility using drugs that block the actions of the RFRP neurons. For women struggling with infertility, drugs which block the actions of the RFRP neurons may prove to be a novel therapy.
The team surmises they have successfully shown that RFRP neurons cause fertility to be suppressed during chronic stress. For the future, the researchers state drugs could one day be used to block the actions of these RFRP neurons, and that will be the focus of further research.
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Michelle is a health industry veteran who taught and worked in the field before training as a science journalist.
Featured by numerous prestigious brands and publishers, she specializes in clinical trial innovation--expertise she gained while working in multiple positions within the private sector, the NHS, and Oxford University.