Quirks & Quarks

The secret to female attraction could be a tiny molecule

A peptide molecule regulates mate preference and sexual behaviour - in female mice
A couple kiss next to of the bonfire on the Poniente beach celebrating the summer solstice in Gijon, Spain, on June 24, 2017. (Eloy Alonso/Reuters)

Just in time for Valentine's day

Researchers have discovered what makes female sexual drive tick - in mice, at least. When female mice detect sex pheremones released by potential mates in the air, it sets off a cascade in the brain that results in the release of an aptly named molecule called kisspeptin. Kisspeptin turns out to be involved in coordinating ovulation, attraction to the opposite sex and sexual behaviour in mice.

The study was led by Professor Ulrich Boehm, Chair of Experimental Pharmacology at Saarland University in Germany, with colleagues in Germany and Belgium.  

A molecular master-switch for reproduction

Kisspeptin is produced by a small subset of neurons in hypothalamus in the brain.  Their work showed that it triggers ovulation to make the release of an egg coincide with the presence of a potential, mate making fertilization that much more likely.  The team also found that kisspeptin causes "lordosis," a reflex in females mice to assume a sexually responsive position.

The team found that only female mice have the particular type of neuron that produces kisspeptin, and they were able to detect the cells producing the molecule when the females smelled the soiled bedding of male mice. You wouldn't think there ws much that was attractive about urine-soaked mouse bedding, but the researchers suggest that urine is rich in pheromones - enough to set the female's ovaries racing to release an egg for the male.

Did we say this is just in mice?

This isn't an argument for rushing off to smell a potential partner's dirty sheets on Valentine's day. Science is still uncertain about how kisspeptin works in our species.  Humans do have kisspeptin genes but we lack something called the vomeronasal organ that is used by mice to detect pheromones. However, there is no doubt that the smell of your partner can trigger feelings of desire and attraction, so you don't need kisspeptin to feel that love.