Second receptor complicates efforts to understand hormone
The mice in Jan-Åke Gustafsson's lab are obese, their bones are brittle, and their spleens are unusually big. The female mice produce fewer and smaller litters than normal mice. They also are more likely to develop high blood pressure and a disease that resembles human leukemia. In fact, problems of one sort or another afflict almost every major organ system in their fragile, overweight bodies.
What these mice lack is the gene for an important molecule needed to fully respond to the hormone estrogen. Known as estrogen receptor beta (ERb), this molecule mediates most of the effects of estrogen not tra