Fig. 3. Quantitative analysis of mammary gland morphogenesis in virgin wild-type and Vdr knockout mice. (A) Fresh weights of surgically dissected mammary gland fat pads from virgin wild-type and Vdr knockout mice (mean±s.e.m., n=10-12 per group), expressed as organ weight to body weight ratio (mg/g). (B) The number of terminal end buds per mammary gland was counted in wholemounts of inguinal glands removed from weight-matched wild-type and Vdr knockout females from 4-10 weeks of age. (C) Ductal extension (defined as the distance from the center of the lymph node to the leading edge of the gland) was measured on inguinal wholemounts from 6-week-old wild-type and Vdr knockout virgin females. (D) The number of primary, secondary and tertiary branch points was quantitated on inguinal wholemounts from 6-week-old wild-type and Vdr knockout virgin females. Data in B-D represent mean±s.e.m. of at least six animals per genotype per time point. *Statistically significant, wild-type versus Vdr knockout (P<0.05).