Brain circuitry finding promises new fertility treatments: New Zealand research

New Zealand scientists Tuesday claimed a breakthrough in understanding how the neural mechanisms of the brain control fertility in humans and other mammals, which could lead to new fertility treatments.

Researchers at the University of Otago said they had the first direct evidence that kisspeptin neurons working simultaneously generated small, episodic hormone pulses that were crucial to normal reproductive functioning in mammals.

Study leader Professor Allan Herbison said that episodic pulses of gonadotropin-releasing hormone (GnRH) to the pituitary gland had long been known to be essential to maintain fertility, but the study had identified the cause of the GnRH pulses.

"These episodic pulses, which occur roughly every hour or so, prompt the pituitary to release two key hormones (LH and FSH) into the bloodstream also in a pulsatile manner," Herbison said in a statement.

It was thought that up to one-third of all cases of infertility in women involved disorders in the area of brain circuitry at the center of the study.

"For example, a very common cause of infertility in women, polycystic ovarian syndrome, is caused when pulses occur too fast, " Herbison said.

Studying mice, the researchers found that selectively activating kisspeptin neurons in a particular part of the brain's hypothalamus was remarkably potent at generating pulses of LH secretion.

When the researchers activated the kisspeptin neurons in mice lacking kisspeptin receptors on their GnRH neurons, no LH pulses were generated.

"These findings represent an important insight that will inform future efforts to develop new fertility treatments aimed at producing more or fewer GnRH pulses, depending on the problem," he said. Endi