Normal mammary gland growth and lactation capacity in pregnant relaxin-deficient mice

Abstract

Pups born to mice with a targeted deletion of relaxin or its receptor (Rxfp1) die within 24 h postpartum. This has been attributed, in part, to abnormal mammary gland development in relaxin-mutant mice (Rln-/-). However, mammary development is normal in relaxin receptor-mutant (Rxfp1 -/-) mice. The present study aimed to verify the mammary phenotypes in late pregnant and early lactating Rln-/- mice and to test the hypothesis that relaxin is involved in milk protein synthesis. Comparisons between late pregnant and early lactating wildtype (Rln+/+) and Rln-/- mice showed no differences in lobuloalveolar structure or ductal branching in the mammary gland. Mammary explants from Rln-/- mice also ..