Normal Growth of Rat Mammary Glands During Pregnancy and Early Lactation.

Abstract
Previous morphological studies were interpreted as indicating complete lobule-alveolar development by first 1/2[long dash]2/3 of pregnancy. By estimation of DNA, a study of rat mammary gland growth was conducted through pregnancy and early lactation. Present data show 20.9% of total growth occurs during the first 10 days of pregnancy, 59.3% by the 20th day of pregnancy, and development is 98.3% complete by the 3rd day of lactation.