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Kisspeptin

Print Print | Email  Email article to a friend | Last updated: December 16, 2014

Kisspeptins are a family of proteins that are essential for fertility. The first gene member of the family was discovered in 1996 by a group working in Hershey, Pennsylvania. It is named after the city’s chocolate ‘Kisses’, which are made in Hershey.

Alternative names for kisspeptin

Metastin.

What is kisspeptin?

Kisspeptin is produced from the hypothalamus and causes a chain reaction which leads to production of neurotransmitters from the pituitary gland. The neurotransmitter signals lead to the release of other hormones (luteinising hormone and follicle stimulating hormone) into the blood. These act on testes and ovaries to produce the sex hormones testosterone and oestradiol, which cause the physical and emotional changes that are well recognised during puberty.

Kisspeptin has a non-hormonal role too and was originally named metastin after its ability to prevent the spread of cancer (metastasis).

How is kisspeptin controlled?

Kisspeptin is released together with two other hormones, neurokinin B and dynorphin. Consequently, the nerve cells making kisspeptin, dynorphin and neurokinin B are popularly referred to as KNDy (pronounced ‘candy’). We are currently trying to understand exactly what neurokinin B and dynorphin hormones do, but they appear to control the release of kisspeptin.

What happens if I have too much kisspeptin?

It is not yet clear whether having too much kisspeptin is good or bad, but a few small studies have linked high levels of kisspeptin during childhood to cases of (early) precocious puberty. More research is now needed to determine if this is the case.

What happens if I have too little kisspeptin?

When kisspeptin cannot act properly on its target cells in the body, it causes infertility in humans. A clinical trial has shown that giving kisspeptin to women with infertility and women who do not menstruate (a condition known as amenorrhoea) can restore the hormone levels in these conditions. Furthermore, a clinical trial has recently shown that a single injection of kisspeptin can trigger ovulation (release of eggs), and these eggs can be artificially fertilised, be placed back inside the womb (in vitro fertilisation), and result in successful pregnancy. Further studies are needed to determine whether kisspeptin will offer improvements in fertility therapy over existing treatments for couples with infertility.

Adolescents who have faulty kisspeptin signalling fail to undergo puberty (hypogonadotrophic hypogonadism), although this is a rare condition.

Recent evidence now suggests kisspeptin might play other roles in the body since it is also present outside the brain, eg, in the placenta and the cardiovascular system. For example, levels of kisspeptin in the blood go up massively (7,000 times!) during pregnancy although the reason why is not yet understood. Intriguingly, a few studies have shown that women who have less kisspeptin in the bloodstream early on in pregnancy may later develop serious complications such as miscarriage or pre-eclampsia (high blood pressure) in the mother, which may cause growth restriction in the unborn baby). It has been suggested by some that measuring kisspeptin during early pregnancy may be a useful screening tool to detect pregnancy complications earlier and hopefully lead to improved care. More research is now needed to determine if this is the case.

 

Reviewed: December 2014

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