The work began when Dr. Mone Zaidi, a professor of medicine at the Icahn School of Medicine at Mount Sinai in New York City, became curious about whether a reproductive hormone F.S.H., or follicle-stimulating hormone affects bone density.
It had long been assumed that the hormones role was limited to reproduction. F.S.H. stimulates the production of eggs in women and sperm in men.
Researchers knew that blood levels of F.S.H. soar as womens ovaries start to fail before menopause. At the same time, women rapidly lose bone even when blood levels of estrogen, which can preserve bone, remain steady.
Dr. Zaidi reasoned that F.S.H. could be a culprit in bone loss. So he and his colleagues created an antibody that blocked F.S.H. in female mice whose ovaries had been removed.
Since the mice were making no estrogen at all, they ought to have been losing bone. Indeed, ...