Mammary gland gestation, serum progesterone remains at a stably high concentration so signaling through its receptor is continuously activated. As one of the transcribed genes, Wnts secreted from mammary epithelial cells act paracrinely to induce more neighboring cells' branching. When the lactiferous duct tree is almost ready, "leaves" alveoli are differentiated from luminal epithelial cells and added at the end of each branch. In late pregnancy and for the first few days after giving birth, colostrum is secreted. Milk secretion (lactation) begins a few days later due to reduction in circulating progesterone and the presence of another important hormone prolactin, which mediates
Safe as Milk Safe as Milk Safe as Milk is the debut album by Captain Beefheart and his Magic Band, released in 1967. A heavily blues-influenced work, the album featured a 20-year-old Ry Cooder, who played guitar and wrote some of the arrangements. Before recording "Safe as Milk", the band had released a couple of singles through A&M Records, and it was to this company that the group first proposed their début album in 1966. They presented the label with a set of R&B-influenced demos, which the label felt were too unconventional and decided to drop the band. Beefheart later said the label