Variation of the Mammary Glands Response of Inbred Female Mice Treated With Estrogen

Variations in mammary response and corrected mammary response of inbred female mice with estrogen treatment were investigated in comparison with those of mice which were randomly and inbred for short time. All mice tested were injected with total doses of 12.5 I. U. of synthetic estrogen five times from 20 days of birth every third day. Mammary response was manifested in mammary area of mice treated with estrogen and further, corrected for body weight.It seemed to be plausible that inbred mice did not show more uniform response in respect to both mammary response and corrected mammary response than the mice which were bred randomly and inbred for short time. Therefore, it was conclued that the use of inbred mice itself might not be necessarily preferred to that of mice which have been kept without inbreeding, in respect to variation of a character chosen to be of the type measured in bio-assay.