British researchers have found that a recently discovered protein called kisspeptin can stimulate the release of reproductive hormones in infertile women, suggesting that the hormone could help restore fertility.
Kisspeptin and the gene that serves as its blueprint, KISS-1, were discovered in Hershey, Penn., in 1999 and named after the city's most famous product, the Hershey's Kiss. At the time, researchers thought that the protein was involved only in suppressing metastasis in certain types of cancer and did not realize the appropriateness of the name.
Biologists later discovered that the protein is produced during puberty, triggering the release of the hormones that bring on puberty. Researchers now hope that finding drugs that block its activity could suppress premature sexuality in some children who begin developing sexual urges at age 5 or 6 because of congenital problems. Conversely, the hormone itself might be used to stimulate puberty in adolescents who do not enter it normally.
In animals, kisspeptin has been shown to play a role in reproduction as well. In seasonally breeding rodents, such as the Siberian hamster, researchers have shown that shorter days lead to diminished production of kisspeptin, which is accompanied by the loss of the reproductive urge. Injecting the hormone into the animals in winter restores the ability to mate.
Two years ago, Dr. Waljit Bhillo of University College London and his colleagues reported that injecting kisspeptin into healthy women stimulated the release of luteinizing hormone and follicle-stimulating hormone, both of which are essential for reproduction.
Now the same team has performed a similar experiment in 10 infertile women, injecting half of them with kisspeptin and half with a placebo. Dhillo reported Monday at a Society for Endocrinology BES meeting in Harrogate, Great Britain, that the kisspeptin increased levels of luteinizing hormone 48-fold and levels of follicle-stimulating hormone 16-fold, far bigger increases than had been observed in healthy women.
"This is a very exciting result and suggests that kisspeptin treatment could restore reproductive function in women with low sex hormone levels," Dhillo said in a statement. "Our future research will focus on determining the best protocol for repeated kisspeptin administration with the hope of developing a new therapy for infertility."
-- Thomas H. Maugh II