Villalpando S, De Santiago S
Unidad de Investigación en Nutrición, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, México, D.F.
Bol Med Hosp Infant Mex. 1993 Dec;50(12):889-97.
The mammary gland integrated by secretory acini has two main physiological goals: the lactogenesis and the milk ejection. The first is controlled by estrogens, prolactin and cortisol; the former by oxytocin. Milk is synthesized through five mechanisms namely: I. Cellular synthesis and exocytosis; 2. Cellular synthesis and exocytosis packed in cell membrane fragment; 3. Passive transport through both cell membranes; 4. Active transport via receptors through both cell membranes, and 5. Paracellular transport. The human milk has a high concentration of lactose and relatively low concentrations of fat and protein in comparison to other species. Its composition varies little in relationship to maternal diet, nevertheless, it holds a close correlation, with body composition of the mother. Exclusively breast-fed infants grow in a similar manner to those formula-fed up to 4-6 months; afterwards growth decelerates, to spurt up the need for complementary food. It has been amply demonstrated that human milk protects against acute infections, both bacterial and viral. The current hospital practices of perinatal care should be changed in our country in order to favour the initiation of breast-feeding. Concerned physicians should have more and precise knowledge about the physiology of lactation in order to help mothers to pursue a successful lactation.
泌乳和排乳。前者受雌激素、催乳素和皮质醇控制；后者受催产素控制。乳汁通过五种机制合成，即：1. 细胞合成与胞吐作用；2. 细胞合成并包裹在细胞膜碎片中进行胞吐作用；3. 通过细胞膜的被动转运；4. 通过受体经细胞膜的主动转运；5. 细胞旁转运。与其他物种相比，人乳中乳糖浓度高，脂肪和蛋白质浓度相对较低。其成分与母亲饮食关系不大，但与母亲的身体组成密切相关。纯母乳喂养的婴儿在4至6个月前的生长方式与配方奶喂养的婴儿相似；之后生长减速，需要添加辅食以加速生长。大量研究表明，人乳可预防细菌和病毒引起的急性感染。我国目前的围产期医院护理做法应加以改变，以促进母乳喂养的开始。相关医生应掌握更多关于泌乳生理的准确知识，以帮助母亲成功进行母乳喂养。
