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Mammary gland

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Colostrum (from Latin , of unknown origin) is the first form of milk produced by the mammary glands of humans and other mammals immediately following delivery of the newborn. It may be called beestings , the traditional word from Old English dialects, when referring to the first milk of a cow or other animals. Most species will begin to generate colostrum just prior to giving birth. Colostrum has an especially high amount of bioactive compounds compared to mature milk to give the newborn the best possible start to life. Specifically, colostrum contains antibodies to protect the newborn against disease and infection, and immune and growth factors and other bioactives that help to activate a newborn's immune system , jumpstart gut function, and seed a healthy gut microbiome in the first few days of life. The bioactives found in colostrum are essential for a newborn's health, growth and vitality. Colostrum strengthens a baby's immune system and is filled with white blood cells to protect it from infection.

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68-499: A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring . Mammals get their name from the Latin word mamma , "breast". The mammary glands are arranged in organs such as the breasts in primates (for example, humans and chimpanzees), the udder in ruminants (for example, cows, goats, sheep, and deer), and the dugs of other animals (for example, dogs and cats). Lactorrhea ,

136-461: A few days later due to reduction in circulating progesterone and the presence of another important hormone prolactin, which mediates further alveologenesis, milk protein production, and regulates osmotic balance and tight junction function. Laminin and collagen in myoepithelial basement membrane interacting with beta-1 integrin on epithelial surface again, is essential in this process. Their binding ensures correct placement of prolactin receptors on

204-468: A functional lactiferous duct tree can be formed again when a female is pregnant again. Tumorigenesis in mammary glands can be induced biochemically by abnormal expression level of circulating hormones or local ECM components, or from a mechanical change in the tension of mammary stroma. Under either of the two circumstances, mammary epithelial cells would grow out of control and eventually result in cancer. Almost all instances of breast cancer originate in

272-403: A glandular portion and a duct portion, the structures of which can be used to classify the gland. Depending on how their products are secreted, exocrine glands are categorized as merocrine , apocrine , or holocrine . Colostrum At birth, the surroundings of the newborn mammal change from the relatively sterile environment in the mother's uterus , with a constant nutrient supply via

340-439: A mature mammary gland are the alveoli (hollow cavities, a few millimeters large), which are lined with milk-secreting cuboidal cells and surrounded by myoepithelial cells . These alveoli join to form groups known as lobules . Each lobule has a lactiferous duct that drains into openings in the nipple . The myoepithelial cells contract under the stimulation of oxytocin , excreting the milk secreted by alveolar units into

408-441: A mother produces is vital to a newborn's health in the first few days of life, research has shown that bovine (cow) colostrum and its components can continue to support important biological activities when given to more mature children and adults, so that the benefits of colostrum can extend well beyond the neonatal period of development. Bovine colostrum and human colostrum are highly similar in their makeup, both containing many of

476-934: A number approximating the number of young typically birthed at a time. The number of teats varies from 2 (in most primates) to 18 (in pigs). The Virginia opossum has 13, one of the few mammals with an odd number. The following table lists the number and position of teats and glands found in a range of mammals: Male mammals typically have rudimentary mammary glands and nipples, with a few exceptions: male mice do not have nipples, male marsupials do not have mammary glands, and male horses lack nipples. The male dayak fruit bat has lactating mammary glands. Male lactation occurs infrequently in some species. Mammary glands are true protein factories, and several labs have constructed transgenic animals , mainly goats and cows , to produce proteins for pharmaceutical use. Complex glycoproteins such as monoclonal antibodies or antithrombin cannot be produced by genetically engineered bacteria , and

544-454: A number of growth factors, such as insulin-like growth factors I (IGF-1), and II, transforming growth factors alpha, beta 1 and beta 2, fibroblast growth factors, epidermal growth factor, granulocyte-macrophage-stimulating growth factor, platelet-derived growth factor, vascular endothelial growth factor, and colony-stimulating factor-1. Colostrum, which is produced for the first two to four days after childbirth, enhances immunity and

612-399: A probable mechanism explaining reductions in gut permeability after colostrum administration in some published studies, while another study found colostrum promising as treatment for distal colitis. Evidence for the beneficial effect of colostrum on extra-gastrointestinal problems is less well developed, due in part to the limited number of randomised double-blind studies published, although

680-416: A role in increasing Ig levels, increasing lymphocyte proliferation stimulating activity and increasing phagocytosis activity. These are supported by other components of colostrum which further enhance the activity of the immune response. The iron binding glycoproteins lactoferrin and transferrin in bovine colostrum assist in attacking pathogens by impacting their cell membrane and making them more susceptible to

748-511: A thin, leaky layer of basement membrane. These hormones promote specific gene expression. Hence cap cells can differentiate into myoepithelial and luminal (duct) epithelial cells, and the increased amount of activated MMPs can degrade surrounding ECM helping duct buds to reach further in the fat pads. On the other hand, basement membrane along the mature mammary ducts is thicker, with strong adhesion to epithelial cells via binding to integrin and non-integrin receptors. When side branches develop, it

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816-528: A variety of possible uses have been suggested. The gut plays several important roles including acting as the main pathway for fluid, electrolyte and nutrient absorption while also acting as a barrier to toxic agents present in the gut lumen including acid, digestive enzymes and gut bacteria. It is also a major immunological defence mechanism, detecting natural commensals and triggering immune response when toxic microbes are present. Failure of homeostasis due to trauma, drugs and infectious microbes not only damages

884-680: Is a downstream effect of mammary gland GHR activation. In any case, unlike IGF-1, GH itself is not essential for mammary gland development, and IGF-1 in conjunction with estrogen can induce normal mammary gland development without the presence of GH. In addition to IGF-1, other paracrine growth factors such as epidermal growth factor (EGF), transforming growth factor beta (TGF-β), amphiregulin , fibroblast growth factor (FGF), and hepatocyte growth factor (HGF) are involved in breast development as mediators downstream to sex hormones and GH/IGF-1. During embryonic development, IGF-1 levels are low, and gradually increase from birth to puberty. At puberty,

952-600: Is a much more "pushing-forward" working process including extending through myoepithelial cells, degrading basement membrane and then invading into a periductal layer of fibrous stromal tissue. Degraded basement membrane fragments (laminin-5) roles to lead the way of mammary epithelial cells migration. Whereas, laminin -1 interacts with non-integrin receptor dystroglycan negatively regulates this side branching process in case of cancer . These complex "Yin-yang" balancing crosstalks between mammary ECM and epithelial cells "instruct" healthy mammary gland development until adult. There

1020-412: Is believed to have anti-inflammatory properties. It is suggested infants fed with human colostrum have lower incidence of gastrointestinal infections . In addition, colostrum also has a laxative effect, encouraging the baby's body to excrete stool, which helps eliminate excess bilirubin . This helps prevent jaundice and allergies in babies. While it has long been understood that the colostrum

1088-526: Is called meconium . This clears excess bilirubin , a waste-product of dead red blood cells which is produced in large quantities at birth due to blood volume reduction from the infant's body, and which is often responsible for jaundice . Newborns have very immature and small digestive systems , and colostrum delivers its bioactives in a very concentrated low-volume form. Colostrum is known to contain immune cells (as lymphocytes ) and many antibodies such as IgA , IgG , and IgM . These are some of

1156-495: Is constantly produced and maintained by rare epithelial cells, dubbed as mammary progenitors which are ultimately thought to be derived from tissue-resident stem cells. Embryonic mammary gland development can be divided into a series of specific stages. Initially, the formation of the milk lines that run between the fore and hind limbs bilaterally on each side of the midline occurs around embryonic day 10.5 (E10.5). The second stage occurs at E11.5 when placode formation begins along

1224-443: 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

1292-404: Is crucial for survival and healthy development. It repairs intestinal damage, improves nutrient absorption, and benefits human and animal babies alike. In calves, colostrum helps develop their gut and prevents death. It reduces infections, antibiotic use, and diarrhea, leading to faster growth and higher profits for farmers. Much like in humans and production animals, companion animal survival in

1360-432: Is preliminary evidence that soybean intake mildly stimulates the breast glands in pre- and postmenopausal women. Secretory alveoli develop mainly in pregnancy, when rising levels of prolactin , estrogen, and progesterone cause further branching, together with an increase in adipose tissue and a richer blood flow . In gestation , serum progesterone remains at a stably high concentration so signaling through its receptor

1428-420: Is probable that little absorption of intact growth factors and antibodies into the bloodstream occurs, due to digestion in the gastrointestinal tract. However, the presence of casein and other buffering proteins does allow growth factors and other bioactive molecules to pass into the lumen of the small intestine intact, where they can stimulate repair and inhibit microbes, working via local effects. This provides

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1496-573: Is the (passive) process of a child or animal ceasing to be dependent on the mother for nourishment. In some species there is complete or partial involution of alveolar structures after weaning, in humans there is only partial involution and the level of involution in humans appears to be highly individual. The glands in the breast do secrete fluid also in nonlactating women. In some other species (such as cows), all alveoli and secretory duct structures collapse by programmed cell death ( apoptosis ) and autophagy for lack of growth promoting factors either from

1564-431: Is the milk produced on the second day after giving birth which is considered best for making this pudding-like delicacy. Colostrum is in very high demand in these states, resulting in product adulteration . Hyperimmune colostrum is natural bovine colostrum collected from a population of cows immunized repeatedly with a specific pathogen. The colostrum is collected within 24 hours of the cow giving birth. Antibodies towards

1632-438: The bloodstream . The liver and pancreas are both exocrine and endocrine glands; they are exocrine glands because they secrete products— bile and pancreatic juice —into the gastrointestinal tract through a series of ducts, and endocrine because they secrete other substances directly into the bloodstream. Exocrine sweat glands are part of the integumentary system; they have eccrine and apocrine types. Exocrine glands contain

1700-469: The placenta , to the microbe-rich environment outside, with irregular oral intake of complex milk nutrients through the gastrointestinal tract . This transition puts high demands on the gastrointestinal tract of the neonate , as the gut plays an important part in both the digestive system and the immune system. Colostrum has evolved to care for highly sensitive mammalian neonates and contributes significantly to initial immunological defense as well as to

1768-463: The ECM or circulating hormones. At the same time, apoptosis of blood capillary endothelial cells speeds up the regression of lactation ductal beds. Shrinkage of the mammary duct tree and ECM remodeling by various proteinase is under the control of somatostatin and other growth inhibiting hormones and local factors. This major structural change leads loose fat tissue to fill the empty space afterward. But

1836-430: The adult human body Exocrine gland Exocrine glands are glands that secrete substances onto an epithelial surface by way of a duct . Examples of exocrine glands include sweat , salivary , mammary , ceruminous , lacrimal , sebaceous , prostate and mucous . Exocrine glands are one of two types of glands in the human body, the other being endocrine glands , which secrete their products directly into

1904-476: The animal has less of an ability to fend off infections and greater prevalence of allergy at both ends of the age spectrum. Stress also affects a companion animal's immune system including changes in environment, diet, etc. Maintaining gut microbial balance is key to maintaining a healthy immune system as well as mucosal integrity, similar to humans. Bovine colostrum has been demonstrated to benefit companion animal immunity and digestive health. Bovine colostrum plays

1972-575: The basal lateral side of alveoli cells and directional secretion of milk into lactiferous ducts. Suckling of the baby causes release of the hormone oxytocin, which stimulates contraction of the myoepithelial cells. In this combined control from ECM and systemic hormones, milk secretion can be reciprocally amplified so as to provide enough nutrition for the baby. During weaning, decreased prolactin, missing mechanical stimulation (baby suckling), and changes in osmotic balance caused by milk stasis and leaking of tight junctions cause cessation of milk production. It

2040-435: The body. The Isle of Man had a local delicacy called "Groosniuys", a pudding made with colostrum. In Finland, a baked cheese called Leipäjuusto is traditionally made with either cow colostrum or reindeer milk. A sweet cheese-like delicacy called 'Junnu' or 'Ginna' is made with colostrum in the south Indian states of Karnataka , Andhra Pradesh and Telangana . It is made with both cow and buffalo milk; in both cases it

2108-465: The case of prototherians, both males and females have functional mammary glands, but their mammary glands are without nipples. These mammary glands are modified sebaceous glands . Concerning most metatherians and eutherians, only females have functional mammary glands, with the exception of some bat species. Their mammary glands can be termed as breasts or udders . In the case of breasts, each mammary gland has its own nipple (e.g., human mammary glands). In

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2176-451: The case of udders, pairs of mammary glands comprise a single mass, with more than one nipple (or teat ) hanging from it. For instance, cows and buffalo udders have two pairs of mammary glands and four teats, whereas sheep and goat udders have one pair of mammary glands with two teats protruding from the udder. Each gland produces milk for a single teat. These mammary glands are evolutionarily derived from sweat glands. The basic components of

2244-444: The cause of the lack of developed mammary glands in males. Mammary gland development is characterized by the unique process by which the epithelium invades the stroma . The development of the mammary gland occurs mainly after birth . During puberty , tubule formation is coupled with branching morphogenesis which establishes the basic arboreal network of ducts emanating from the nipple . Developmentally, mammary gland epithelium

2312-484: The components of the adaptive immune system. Other immune components of colostrum include the major components of the innate immune system, such as lactoferrin , lysozyme , lactoperoxidase , complement , and proline-rich polypeptides (PRP). A number of cytokines (small messenger peptides that control the functioning of the immune system) are found in colostrum as well, including interleukins, tumor necrosis factor, chemokines, and others. Colostrum also contains

2380-611: The connective tissue. They not only help to support mammary basic structure, but also serve as a communicating bridge between mammary epithelia and their local and global environment throughout this organ's development. A mammary gland is a specific type of apocrine gland specialized for manufacture of colostrum (first milk) when giving birth. Mammary glands can be identified as apocrine because they exhibit striking "decapitation" secretion. Many sources assert that mammary glands are modified sweat glands . Mammary glands develop during different growth cycles. They exist in both sexes during

2448-471: The cow's bloodstream and in the colostrum. These immunoglobulins are specific to many human pathogens , including Escherichia coli , Cryptosporidium parvum , Shigella flexneri , Salmonella species , Staphylococcus species, and rotavirus (which causes diarrhea in infants). Before the development of antibiotics, colostrum was the main source of immunoglobulins used to fight bacteria. In fact, when Albert Sabin made his first oral vaccine against polio,

2516-411: The ductal systems undergo rapid proliferation and form alveolar structures within the branches to be used for milk production. After delivery, lactation occurs within the mammary gland; lactation involves the secretion of milk by the luminal cells in the alveoli. Contraction of the myoepithelial cells surrounding the alveoli will cause the milk to be ejected through the ducts and into the nipple for

2584-421: The ducts invading towards the lymph node . Terminal end buds, the highly proliferative structures found at the tips of the invading ducts, expand and increase greatly during this stage. This developmental period is characterized by the emergence of the terminal end buds and lasts until an age of about 7–8 weeks. By the pubertal stage, the mammary ducts have invaded to the end of the mammary fat pad. At this point,

2652-411: The eggs of early mammals moist and free from infection (monotremes still lay eggs). Other theories suggest that early secretions were used directly by hatched young, or that the secretions were used by young to help them orient to their mothers. Lactation is thought to have developed long before the evolution of the mammary gland and mammals; see evolution of lactation . List of distinct cell types in

2720-533: The embryonic stage, forming only a rudimentary duct tree at birth. In this stage, mammary gland development depends on systemic (and maternal) hormones, but is also under the (local) regulation of paracrine communication between neighboring epithelial and mesenchymal cells by parathyroid hormone-related protein ( PTHrP ). This locally secreted factor gives rise to a series of outside-in and inside-out positive feedback between these two types of cells, so that mammary bud epithelial cells can proliferate and sprout down into

2788-537: The epithelial cells' " niche " can be delicately unique with different membrane receptor profiles and basement membrane thickness from specific branching area to area, so as to regulate cell growth or differentiation sub-locally. Important players include beta-1 integrin , epidermal growth factor receptor (EGFR), laminin-1/5 , collagen-IV , matrix metalloproteinase (MMPs), heparan sulfate proteoglycans , and others. Elevated circulating level of growth hormone and estrogen get to multipotent cap cells on TEB tips through

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2856-419: The growth, development, and maturation of the neonate's gastrointestinal tract by providing key nutrients and bioactive factors. Bovine colostrum powder is rich in protein and low in sugar and fat. Bovine colostrum can also be used for a range of conditions in humans, and can boost a neonate's immunity. Colostrum also has a mild laxative effect, encouraging the passing of a baby's first stool , which

2924-757: The gut but can lead to influx of damaging agents into the bloodstream. These mechanisms have relevance for multiple conditions affecting all areas of the world and socioeconomic groups such as ulcers, inflammation, and infectious diarrhea. There is currently much interest in the potential value of colostrum for the prevention and treatment of these conditions as it is derived from natural sources and can influence damaging factors through multiple pathways including nutritional support, immunological intervention (through its immunoglobulin and other anti-microbial factors) and growth/healing factor constituents. As pointed out by Kelly, inconsistency between results in some published studies may be due in part to variation in dose given and to

2992-571: The immune and digestive systems are developing and maturing. Bovine colostrum provides macro- and micro-nutrients, as well as growth factors, cytokines, nucleosides, oligosaccharides, natural antimicrobials, antioxidants; and a range of immunoglobulins such as IgG, IgA, IgD, IgM and IgE. It is well established that minimal levels of IgG are essential to prevent failure of passive transfer. The iron-binding glycoproteins lactoferrin and transferrin in bovine colostrum assist in attacking pathogens by impacting their cell membrane and making them more susceptible to

3060-575: The immune systems attack by neutrophils. Cytokines present in bovine colostrum enhance B and T cell maturation and increase endogenous antibody production. They also play a major role in regulation of epithelial cell growth and development, proliferation, and restitution. Transfer factors enhance the activity of T cells. Other growth and immune factors such as IGF-1, IGF-2, FGF, EGF, TGF, PDGF, etc. Bovine colostrum boosts immunity and gut health in all animals. Its rich bioactive components fight bacteria, viruses, and other pathogens. Early, high-quality colostrum

3128-757: The immune systems attack by neutrophils. Cytokines present in bovine colostrum enhance B and T cell maturation and increase endogenous antibody production. They also play a major role in regulation of epithelial cell growth and development, proliferation, restitution. Transfer factors enhance the activity of T cells. Other growth and immune factors such as IGF-1, IGF-2, FGF, EGF, TGF, PDGF, etc. Colostrum contains glycomacropeptides which help to regulate appetite. Bovine colostrum boosts animal immunity, leading to stronger vaccine responses, improved gut health, and reduced illness from diarrhea and respiratory issues. Dairy cattle are naturally exposed to pathogens and produce immunoglobulins against them. These antibodies are present in

3196-526: The immunization is by surface antigens of the bacteria, the Bovine Colostrum Powder can be used to make tablets capable of binding to the bacteria so that they are excreted in stools. This prevents the successful colonization of the gut, which would otherwise lead to bacteria releasing enterotoxigenic materials. These small immune signaling peptides (PRPs) were independently discovered in colostrum and other sources, such as blood plasma, in

3264-479: The immunoglobulin he used came from bovine colostrum. When antibiotics began to appear, interest in colostrum waned, but, now that antibiotic-resistant strains of pathogens have developed, interest is once again returning to natural alternatives to antibiotics, namely, colostrum. Although bovine colostrum has been consumed by humans for centuries, only in recent decades have we seen an increase in randomized clinical trials to support assertions of health benefits. It

3332-411: The intestine of the neonate. The newborn animal must receive colostrum within 6 hours of being born for maximal absorption of colostral antibodies to occur. Recent studies indicate that colostrum should be fed to bovines within the first thirty minutes to maximize IgG absorption rates. The role of colostrum for newborn animals is to provide nutrition, and essential protection against infection while

3400-898: The levels of GH and IGF-1 reach their highest levels in life and estrogen begins to be secreted in high amounts in females, which is when ductal development mostly takes place. Under the influence of estrogen, stromal and fat tissue surrounding the ductal system in the mammary glands also grows. After puberty, GH and IGF-1 levels progressively decrease, which limits further development until pregnancy , if it occurs. During pregnancy, progesterone and prolactin are essential for mediating lobuloalveolar development in estrogen-primed mammary gland tissue, which occurs in preparation of lactation and nursing . Androgens such as testosterone inhibit estrogen-mediated mammary gland development (e.g., by reducing local ER expression) through activation of androgen receptors expressed in mammary gland tissue, and in conjunction with relatively low estrogen levels, are

3468-565: The lobule lumen toward the nipple. As the infant begins to suck, the oxytocin-mediated "let down reflex" ensues, and the mother's milk is secreted—not sucked—from the gland into the infant's mouth. All the milk-secreting tissue leading to a single lactiferous duct is collectively called a "simple mammary gland"; in a "complex mammary gland", all the simple mammary glands serve one nipple. Humans normally have two complex mammary glands, one in each breast, and each complex mammary gland consists of 10–20 simple glands. The opening of each simple gland on

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3536-412: The lobules or ducts of the mammary glands. The breasts of female humans vary from most other mammals that tend to have less conspicuous mammary glands. The number and positioning of mammary glands varies widely in different mammals. The protruding teats and accompanying glands can be located anywhere along the two milk lines . In general most mammals develop mammary glands in pairs along these lines, with

3604-500: The lymph system. A basement membrane, mainly containing laminin and collagen , formed afterward by differentiated myoepithelial cells, keeps the polarity of this primary duct tree. These components of the extracellular matrix are strong determinants of duct morphogenesis. Estrogen and growth hormone (GH) are essential for the ductal component of mammary gland development, and act synergistically to mediate it. Neither estrogen nor GH are capable of inducing ductal development without

3672-705: The mammary glands become smaller. Lactiferous duct development occurs in females in response to circulating hormones . First development is frequently seen during pre- and postnatal stages, and later during puberty . Estrogen promotes branching differentiation, whereas in males testosterone inhibits it. A mature duct tree reaching the limit of the fat pad of the mammary gland comes into being by bifurcation of duct terminal end buds (TEB), secondary branches sprouting from primary ducts and proper duct lumen formation. These processes are tightly modulated by components of mammary epithelial ECM interacting with systemic hormones and local secreting factors. However, for each mechanism

3740-504: The mammary milk line. This will eventually give rise to the nipple. Lastly, the third stage occurs at E12.5 and involves the invagination of cells within the placode into the mesenchyme , leading to a mammary anlage (biology) . The primitive (stem) cells are detected in embryo and their numbers increase steadily during development Postnatally , the mammary ducts elongate into the mammary fat pad. Then, starting around four weeks of age, mammary ductal growth increases significantly with

3808-401: The mesenchymal layer until they reach the fat pad to begin the first round of branching. At the same time, the embryonic mesenchymal cells around the epithelial bud receive secreting factors activated by PTHrP , such as BMP4 . These mesenchymal cells can transform into a dense, mammary-specific mesenchyme, which later develop into connective tissue with fibrous threads, forming blood vessels and

3876-465: The newborn stage of life is largely dependent upon colostrum. Companion animal immune systems require several weeks to several months in order to fully develop. Maternal antibodies provide benefit for a relatively short period of time so a gap exists with immune sufficiency where an animal is at risk of infection. Like humans, companion animal immune response changes with age where early life and later in life have similarities. That is, an immune bias whereby

3944-485: The nursing infant. Upon weaning of the infant, lactation stops and the mammary gland turns in on itself, a process called involution . This process involves the controlled collapse of mammary epithelial cells where cells begin apoptosis in a controlled manner, reverting the mammary gland back to a pubertal state. During postmenopause , due to much lower levels of estrogen, and due to lower levels of GH and IGF-1, which decrease with age, mammary gland tissue atrophies and

4012-516: The occasional production of milk by the glands, can occur in any mammal, but in most mammals, lactation , the production of enough milk for nursing , occurs only in phenotypic females who have gestated in recent months or years. It is directed by hormonal guidance from sex steroids . In a few mammalian species, male lactation can occur. With humans, male lactation can occur only under specific circumstances. Mammals are divided into 3 groups: prototherians , metatherians , and eutherians . In

4080-491: The other. The role of GH in ductal development has been found to be mostly mediated by its induction of the secretion of insulin-like growth factor 1 (IGF-1), which occurs both systemically (mainly originating from the liver ) and locally in the mammary fat pad through activation of the growth hormone receptor (GHR). However, GH itself also acts independently of IGF-1 to stimulate ductal development by upregulating estrogen receptor (ER) expression in mammary gland tissue, which

4148-596: The production in live mammals is much cheaper than the use of mammalian cell cultures . There are many theories on how mammary glands evolved. For example, it is thought that the mammary gland is a transformed sweat gland, more closely related to apocrine sweat glands . Because mammary glands do not fossilize well, supporting such theories with fossil evidence is difficult. Many of the current theories are based on comparisons between lines of living mammals— monotremes , marsupials , and eutherians . One theory proposes that mammary glands evolved from glands that were used to keep

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4216-419: The same antibodies, immune and growth factors, and other nutrients. Because they share so many of the same components, the way they work in the body is also highly similar. The benefit of bovine colostrum for human health has been studied in many areas including: There is also research suggesting that a large proportion of colostrum is not fit for human consumption "due to tremendous bacterial loads". Salmonella

4284-401: The specific pathogens or antigens that were used in the immunization are present in higher levels than in the population before treatment. Although some papers have been published stating that specific human pathogens were just as high as in hyperimmune colostrum, and natural colostrum nearly always had higher antibody titers than did the hyperimmune version. Clinical trials have shown that if

4352-536: The surface of the nipple is called a "pore." The presence of more than two nipples is known as polythelia and the presence of more than two complex mammary glands as polymastia . Maintaining the correct polarized morphology of the lactiferous duct tree requires another essential component – mammary epithelial cells extracellular matrix (ECM) which, together with adipocytes , fibroblast , inflammatory cells, and others, constitute mammary stroma. Mammary epithelial ECM mainly contains myoepithelial basement membrane and

4420-456: The terminal end buds become less proliferative and decrease in size. Side branches form from the primary ducts and begin to fill the mammary fat pad. Ductal development decreases with the arrival of sexual maturity and undergoes estrous cycles (proestrus, estrus, metestrus, and diestrus). As a result of estrous cycling, the mammary gland undergoes dynamic changes where cells proliferate and then regress in an ordered fashion. During pregnancy ,

4488-534: The timing of the colostrum collection being tested (first milking versus pooled colostrum collected up to day 5 following calving). Some athletes have used colostrum in an attempt to improve their performance, decrease recovery time, and prevent sickness during peak performance levels. Supplementation with bovine colostrum, 20 grams per day (g/d), in combination with exercise training for eight weeks may increase bone-free lean body mass in active men and women. Low IGF-1 levels may be associated with dementia in

4556-560: The very elderly, although causation has not been established. Malnutrition can cause low levels of IGF-1, as can obesity. Supplementation with colostrum, which is rich in IGF-1, can be a useful part of a weight reduction program. Although IGF-1 is not absorbed intact by the body, some studies suggest it stimulates the production of IGF-1 when taken as a supplement whereas others do not. Colostrum also has antioxidant components, such as lactoferrin and hemopexin , which binds free heme in

4624-418: Was also detected in 15% of unpasteurised samples. Pasteurisation reduces the bioactive proteins many of the benefits rely upon, however. Colostrum is crucial for newborn farm animals. They receive no passive transfer of immunity via the placenta before birth, so any antibodies that they need have to be ingested (unless supplied by injection or other artificial means). The ingested antibodies are absorbed from

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