Abstract
The mammary growth in normal female mice treated with estrogen was compared with that in intact female mice as a side work of breeding experiment in mice with special reference to the sensitivity of mammary gland. Half of females produced from 18 parents were injected with a standard dose of estrogen and the other half were kept without any treatment until 35 days after birth.
Results obtained are as follows:
1. No difference was found in body weight between treated and intact female mice on both 20 days and 35 days after birth.
2. Differences of mammary gland area and uterine weight were found between two groups.
3. Variance of mammary gland area in treated mice seemed to be smaller than that in intact mice. The fact might be caused by the decrease of relative variation of amount of estrogen acting on the mammary gland.
