Twice-weekly injections of the hormone kisspeptin may provide a new treatment to restore fertility in some women, according to research presented last month at the Society for Endocrinology BES meeting in Manchester.
The findings show that twice-weekly injections can lead to increases in the levels of sex hormones, which control the menstrual cycle. This is the first study to show this effect can be maintained over the long term and it may lead to new therapies for women whose infertility is due to low sex hormone levels.
Kisspeptin is a product of the KISS-1 gene and is a key regulator of reproductive function. Animals and humans lacking kisspeptin function do not go through puberty and remain sexually immature.
A team led by Dr Waljit Dhillo of Imperial College London studied women with a condition called hypothalamic amenorrhoea, where a deficiency in sex hormone levels prevents menstruation, resulting in infertility.
Previously, Dr Dhillo’s group found that a one-off injection of kisspeptin caused an increase in sex hormone production in these women, but further daily administration was not effective as the system stopped responding.
The aim of the present study was to examine kisspeptin’s potential as a fertility treatment by finding a dose regimen that would maintain sex hormone production over a sustained period of time.
Over eight weeks, a group of ten women with hypothalamic amenorrhoea were either given twice-weekly injections of kisspeptin (n=5) or twice-weekly injections of saline as a control (n=5).
Blood samples were taken at regular intervals to measure their levels of luteinising hormone (LH) and follicle stimulating hormone (FSH). Women demonstrated a large increase in circulating sex hormones on day zero (mean maximal LH increase 21.5IU/l), which was halved to 10.0IU/l on day 14.
However, after day 14, their responsiveness to the kisspeptin treatment remained steady. On the last day of the trial, women who had been given kisspeptin injections showed a 16-fold increase in their hormonal response, compared to the saline controls.
This is the first long-term clinical study to examine the effectiveness of kisspeptin treatment. Twice-weekly injections of kisspeptin, administered over a two-month period, can successfully stimulate the release of sex hormones in women with infertility due to hypothalamic amenorrhoea and this treatment does not cause any side-effects. These findings now need to be confirmed in large-scale randomised trials, before any treatments can be brought into clinical practice.