All Phenotypes Xdh<tm1Mrc> MGI Mouse

abnormal involution of the mammary gland ( J:80993 )

• heterozygotes display premature involution of the mammary gland at lactation day 11

abnormal mammary gland growth during lactation ( J:80993 )

• at lactation day 11, the heterozygous mammary epithelium shows severe cell shedding and tissue fragmentation with loss of epithelial tissue volume and premature tissue involution

• by lactation day 13, an overall collapse of mammary epithelial tissue is observed

• only milk secreting alveoli are affected, while ducts, which transport secretions to the exterior of the gland, appear normal

• mammary tissue destruction is independent of a defect in lactogenic hormones and correlates with the time course of pup starvation

abnormal lactation ( J:80993 )

• heterozygotes are unable to maintain lactation due to failure to secrete fat droplets into milk; as a result, their pups die of starvation within 2 weeks postpartum

abnormal milk composition ( J:80993 )

• heterozygotes show defective enveloping of milk fat droplets with the apical mammary epithelial membrane, resulting in impaired secretion of droplets into milk

decreased body weight ( J:80993 )

• pups nursed by heterozygous mothers begin to appear visibly malnourished by P6

• by P12, pups are emaciated, and by P13, remaining pups display less than 50% of wild-type body weight

• pups from heterozygous females can be raised normally by wild-type mothers

decreased total body fat amount ( J:80993 )

• pups born to heterozygous females are devoid of adipose tissue e.g. brown fat and mammary fat pads

abnormal skeletal muscle morphology ( J:80993 )

• pups born to heterozygous females show reduced skeletal muscle volume, consistent with starvation