Biomaterial Database

Changes in human milk composition during the initiation of lactation. 1981

J K Kulski, and P E Hartmann

Studies were undertaken to determine the progressive changes and relationships between the major constituents in the mammary secretion of breast feeding and non-breast feeding women during the initiation of lactation. The concentration of metabolites (lactose, glucose and urea), electrolytes and proteins (total protein, alpha-lactalbumin, lactoferrin, albumin, IgA, IgG and IgM) were measured in small samples of mammary secretion (0 . 5-5 . 0 ml). Colostrum during late pregnancy contained higher concentrations of proteins and lower concentrations of metabolites than milk in established lactation. Of the electrolytes, the concentrations of sodium, chloride and magnesium were higher, whereas potassium and calcium were lower in colostrum than in milk. The osmolality of the secretion remained relatively constant over the pre-partum and post-partum period. These findings showed that the initiation of lactation developed in two phases, first a limited secretion of milk constituents in late pregnancy and then true induction of lactation (lactogenesis) 32-40 h after delivery. The changes in the mammary secretion of non-breast feeding women during the first 3 days post-partum were similar to those observed in breast feeding women but reversed abruptly during the next 6 days, indicating the onset of mammary involution. This finding demonstrated that breast feeding is not a major factor for the initiation of lactation but is essential for the continuation of full lactation.

UI	MeSH Term	Description	Entries
D007136	Immunoglobulins	Multi-subunit proteins which function in IMMUNITY. They are produced by B LYMPHOCYTES from the IMMUNOGLOBULIN GENES. They are comprised of two heavy (IMMUNOGLOBULIN HEAVY CHAINS) and two light chains (IMMUNOGLOBULIN LIGHT CHAINS) with additional ancillary polypeptide chains depending on their isoforms. The variety of isoforms include monomeric or polymeric forms, and transmembrane forms (B-CELL ANTIGEN RECEPTORS) or secreted forms (ANTIBODIES). They are divided by the amino acid sequence of their heavy chains into five classes (IMMUNOGLOBULIN A; IMMUNOGLOBULIN D; IMMUNOGLOBULIN E; IMMUNOGLOBULIN G; IMMUNOGLOBULIN M) and various subclasses.	Globulins, Immune,Immune Globulin,Immune Globulins,Immunoglobulin,Globulin, Immune
D007768	Lactalbumin	A major protein fraction of milk obtained from the WHEY.	alpha-Lactalbumin,alpha-Lactalbumin A,alpha-Lactalbumin B,alpha-Lactalbumin C,alpha Lactalbumin,alpha Lactalbumin A,alpha Lactalbumin B,alpha Lactalbumin C
D007774	Lactation	The processes of milk secretion by the maternal MAMMARY GLANDS after PARTURITION. The proliferation of the mammary glandular tissue, milk synthesis, and milk expulsion or let down are regulated by the interactions of several hormones including ESTRADIOL; PROGESTERONE; PROLACTIN; and OXYTOCIN.	Lactation, Prolonged,Milk Secretion,Lactations, Prolonged,Milk Secretions,Prolonged Lactation,Prolonged Lactations
D007781	Lactoferrin	An iron-binding protein that was originally characterized as a milk protein. It is widely distributed in secretory fluids and is found in the neutrophilic granules of LEUKOCYTES. The N-terminal part of lactoferrin possesses a serine protease which functions to inactivate the TYPE III SECRETION SYSTEM used by bacteria to export virulence proteins for host cell invasion.	Lactotransferrin
D007785	Lactose	A disaccharide of GLUCOSE and GALACTOSE in human and cow milk. It is used in pharmacy for tablets, in medicine as a nutrient, and in industry.	Anhydrous Lactose,Lactose, Anhydrous
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D008894	Milk Proteins	The major protein constituents of milk are CASEINS and whey proteins such as LACTALBUMIN and LACTOGLOBULINS. IMMUNOGLOBULINS occur in high concentrations in COLOSTRUM and in relatively lower concentrations in milk. (Singleton and Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed, p554)	Milk Protein,Protein, Milk,Proteins, Milk
D008895	Milk, Human	Milk that is produced by HUMAN MAMMARY GLANDS.	Breast Milk,Human Milk,Milk, Breast
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation