Kisspeptin is a hormone coded by the KiSS-1 gene. This gene was discovered in Hershey, Pennsylvania, and researchers decided to name it after the town's most famous product, the Hershey chocolate "Kiss". Animals and humans lacking kisspeptin function do not go through puberty and remain sexually immature.

The scientists at Imperial College injected a small group of healthy female volunteers with the hormone kisspeptin. Soon after injection the volunteers showed a rise in their circulating concentrations of luteinising hormone (LH), a hormone which can be used to stimulate the ovary in fertility treatment. Kisspeptin increased LH concentrations at all stages of the menstrual cycle, but the effect was greatest in the pre ovulation phase, which is essential for fertility. This is the first time that kisspeptin has been shown to have a stimulatory effect on LH in women.

It's likely that the next steps will be to test the effects of kisspeptin in patients with disorders of sexual regulation.

Researcher Dr Waljit Dhillo said:

Kisspeptin has previously been shown to potently stimulate hormone release in animals, but this is the first time that it has been shown to stimulate sex hormone release in women. Kisspeptin is a promising new tool for the restoration of normal reproductive function in women with low sex hormone levels'.

endocrinology

"The induction of beta-endorphin appears to be hard-wired to the tanning pathway," Fisher said. "This might explain addictive behaviors associated with sun-seeking or the use of tanning salons."

The researchers observed similar events in human skin to those seen in the mice. They also found evidence implicating p53 in other forms of abnormal skin pigmentation that can result as a side effect of certain drugs or other stresses.

"Certain drugs are probably inadvertently activating p53 and, with it, the sun-tanning pathway," Fisher speculated. "We might now be able to find ways to interfere with this process to prevent it from occurring."

By the same token, a more complete understanding of the suntan process could lead to products that can produce a tan safely without exposure to potentially damaging UV radiation-even in those people who otherwise don't tan. Fisher said he is involved in a small biotechnology company that is working to develop such a product.

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