Peg3 conditional knockout dams: milk letdown.

Milk retention at 10 dpp of MMTV-driven (a) and Nkx2.1-driven (b) deletions in Peg3 are shown as a function of the weight change between every two hours in the dam subtracted by the weight change between the same time points in the pups. Therefore, the weight flux shown is a measure of how much nutrient transfer is occurring from the dam to her pups at each given time interval with positive slopes indicating weight gain in the dam that is not transferred over to the pups. Conversely, negative slopes indicate a dam giving all her mass to the pups, without gaining any weight herself. The dashed black box indicates the critical point wherein reintroduction of the dams to their pups has just occurred. (c) Oxytocin-induced milk ejection was surveyed in MMTV-driven Peg3 deleted mice alongside wild-type littermate controls. Black arrows indicate ductal branches in the mammary gland.