Two naturally occurring animal hormones are largely responsible for controlling the development and size of fat cells in fetal pigs. The two hormones may work best together, ac-cording to scientists with USDA's Agricultural Research Service.

Thyroxine, a hormone of the thyroid gland, increases fat cell numbers, while fat cell size is controlled by hydrocortisone, an adrenal hormone. The two hormones work together to give fetal pigs the sustaining layers of fat they will need after birth.

The study's results suggest the potential for producing leaner pork by reducing the levels of one of the hormones in a fetal pig or piglet. The theory is that this might be influenced by genetics or through treatments as the pig grows.

The research is in the early stages and more is planned for the future.