Milk synthesis

Farrell, H. M., Jr., Malin, E. L., Brown, E. M., and Qi, P. X. (2006). Casein micelle structure What can be learned from milk synthesis and structural biology Curr. Opin. Colloid Interface Sci. 11,135-147. 

The substrates for milk synthesis enter the secretory cell across the basal membrane (outside), are utilized, converted and interchanged as they pass inwards through the cell and the finished milk constituents are excreted into the lumen across the lumenal or apical membrane. Myoepithelial cells (spindle shaped) form a basket around each alveolus and are capable of contracting on receiving an electrical, hormonally mediated, stimulus, thereby causing ejection of milk from the lumen into the ducts. 

The arterial and veinous systems supplying the mammary gland (Figure 1.5) are readily accessible and may be easily cannulated to obtain blood samples for analysis. Differences in composition between arterial and venous blood give a measure of the constituents used in milk synthesis. The total amount of constituent used may be determined if the blood flow rate is known, which may be easily done by infusing a known volume of cold saline... 

Luick, J. R. and Mazrimas, J, A. 1966. Biological effects of ionizing radiation on milk synthesis. III. Effects on milk lipase, esterase, alkaline phosphatase, and lactoper-oxidase activities. J. Dairy Sci. 49, 1500-1504. 

General anabolic effects stimulates release of insulinlike growth factor-I Stimulates milk synthesis Ovary luteinization, progesterone synthesis testis interstitial cell development, androgen synthesis... 

Receptors for l,25(OH)2D3 have also been described in the mammary gland [26,27], where a major calcium and phosphorus translocation must take place in order to provide the essential amounts of these minerals for milk synthesis. However, this process does not seem to be under the dependence of vitamin D since, at least in small mammals (rat, mouse) the mineral content of milk is not significantly affected by the vitamin D-deficiency of the mother [52]. 

In addition to long-chain fatty acids from plasma, the major nutrients utilized for milk fat synthesis are glucose, acetate and 0-hydroxybutyrate. Kinetics for the uptake of these from blood were reported by Miller et al. (1991). Glucose is absolutely required for milk synthesis, being a precursor for lactose or other carbohydrates, or both, in all terrestrial mammals (Oftedal and Iverson, 1995). 

Nielsen, M.O., Jakobsen, K. 1994. Changes in mammary uptake of free fatty acids, triglyceride, cholesterol and phospholipid in relation to milk synthesis during lactation in goats. Comp. Biochem. Physiol. 109A, 857-867. 

Effect of opioids on the activity of some key enzymes involved in milk synthesis in mammary gland of lactating rabbit Hossain, M. A. Ganguli, N. C. 

Status of opioids in bovine milk and its influence on enzymes in milk synthesis Hossain, M. Afzal Kumar, Amalendra Ganguli, N. C. 

In the US system, NE values for lactation (NEj) are calculated fromTDN, DE or NE by an equation similar to that used in the Dutch system. For example, in the US system, foods containing 10 or 12 MJ ME/kg DM would be calculated to provide 6.0 and 7.1 MJ NEi/kg DM, respectively, whereas in the Dutch system, they would be calculated to provide 5.8 and 7.2 MJ NEi/kg DM, respectively. Net energy requirements for body maintenance and milk synthesis are expressed as NE, as they are in the Dutch and related European systems. 

Leiber, F., M. Kreuzer, B. Joig, H. Leuenberger and H.R. Wettstein, 2004. Contribution of altitude and alpine origin of forage to the influence of alpine sojourn of cows on intake, nitrogen conversion, metabolic stress and milk synthesis. Anim. Sci. 78,451-466. 

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