Requirement of essential fatty acids in the diet for development of the mouse mammary gland.

The ductal system of mammary glands in C3H mice that were started on diets deficient in essential fatty acid(s) (EFA) 1--2 weeks after weaning developed at a normal rate. The alveolar structures, however, began to disappear in the mice after 17 weeks on the EFA-deficient regimen. Injection sc of linoleic acid prevented the atrophic process. Alveoli were also absent in the glands of multiparous mice that were maintained for 32 weeks on the EFA-deficient diet. When the EFA-deficient regimen was started in females during midpregnancy and maintained continuously thereafter, both ductal and alveolar structures failed to develop in the mammary glands of the offspring. Linoleic acid appears to be required for development of ductal and alveolar structures during growth of the mammary gland and also for maintenance of the alveolar structures in the adult mammary gland.