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
Grade A Pasteurized Milk Ordinance PMO standards as a minimum, and in many cases requires more stringent standards. Grade A Pasteurized Milk Ordinance The Grade A Pasteurized Milk Ordinance, published by the Food and Drug Administration, outlines minimum standards and requirements for Grade A milk production and processing. Grade A standards are recommended by the National Conference on Interstate Milk Shipments (NCIMS), which is composed of voting representatives from state and local regulatory agencies, and nonvoting representatives of the dairy industry and FDA. As a general rule, FDA accepts the Conference recommendations and incorporates them into the revised PMO. The state regulator (which is usually