Researchers found a new potential cause of male pattern baldness, a discovery verified in mice that suggests new avenues for treatments, according to a study published Wednesday.

Dermatologists linked balding to increased levels of a hormone that inhibits hair growth, and researchers found that mice flooded with the hormone develop alopecia.

Prostaglandin D2 (PGD2) hormone inhibited hair growth in mice and cultured human hair follicles, according to the study. Researchers also found men with male pattern baldness had increased hormone levels in hairless sections of their scalp and decreased PGD2 in hairy sections.

PGD2  hormone binds to a receptor that researchers hypothesized turns on a pathway that leads to atrophy and eventual destruction of hair follicles.

The next step would be to screen for compounds that affect this receptor and to also find out whether blocking that receptor would reverse balding or just prevent balding, George Cotsarelis, the study's author and a hair and scalp disorder researcher at the University of Pennsylvania, told BBC News.

About 80 million men and women in the U.S. have hair loss and balding affects 80 percent of men under the age of 70, according to the American Academy of Dermatology. Symptoms of male pattern baldness include hair thinning and a receding hairline that eventually leads to a horseshoe-shaped hair pattern.

Researchers previously identified other functions for the hormone. PGD2 causes airway constriction and asthma patients have higher than normal levels of the protein, according to researchers. Existing drugs that target the protein in asthmatics could be adapted to stop balding, researchers said.

The nice thing about dermatology and hair loss in general is that you can take compounds that maybe are being used as a pill and put them in a topical formulation, Cotsarelis told the Daily Mail. When you apply this to the scalp, you would allow hair to grow.

A drug could be on sale within five years, Cotsarelis told the Daily Mail.

We need new treatments, as the available ones are OK, but they are not great, Neil Sadick, a professor of dermatology at Weill Cornell Medical College in New York, who wasn't involved with the study, told WebMD. If we have something that acts on a different pathway, it could be more effective.

The current treatments for baldness include minoxidil, branded as Rogaine, which is available as a topical liquid or foam; and Propecia, a pill originally designed to treat an enlarged prostate.

The journal Science Translational Medicine published the study on Wednesday.