Physiology of Lactation.
- Author:
Ee Kyung KIM
1
Author Information
- Publication Type:Review
- Keywords: Milk synthesis; Prolactin; Oxytocin; Let-down
- MeSH: Animals; Breast; Breast Feeding; Central Nervous System; Contracts; Dietary Sucrose; Exocytosis; Female; Fertility; Gonadotropin-Releasing Hormone; Humans; Hypothalamus; Ions; Lactation; Mammary Glands, Human; Milk; Milk Ejection; Oxytocin; Parturition; Postpartum Period; Pregnancy; Progesterone; Prolactin; Secretory Pathway; Transcytosis; Water
- From:Hanyang Medical Reviews 2010;30(1):1-7
- CountryRepublic of Korea
- Language:Korean
- Abstract: To produce milk, four secretory processes are synchronized in the alveolar cell of the mature, functional mammary gland: (1) exocytosis, (2) fat synthesis and secretion, (3) secretion of ions and water, and (4) transcytosis of immunoglubulins and other substances from the interstitial space. Milk is synthesized continuously into the alveolar lumen, where it is stored until milk removal from the breast is initiated. Prolactin mediates the central nervous system regulation of milk secretion, but its influence is modified greatly by local factors that depend on milk removal from the breast. Oxytocin mediates milk let-down by stimulating the contraction of myoepithelial cells that surround the alveoli and ducts. Lactogenesis includes all the processes necessary to go from the undifferentiated mammary gland in the early pregnant animal to full lactation sometime after parturition. The most important factors in initiation of lactogenesis stage II appear to be progesterone withdrawal. The metabolic demands of breastfeeding require an increase in maternal metabolism. Postpartum suppression of fertility is thought to be the result of an alteration in pulsatile gonadotropin releasing hormone secretion from the hypothalamus. Women who wish to ensure against pregnancy during lactation usually are advised to use other contraceptive means.
