Effects of fasting during mid pregnancy or early lactation on mammary development and milk yield in mice

Knight, Christopher H.; Peaker, M.

doi:10.1017/s0022029900022718

Cited by 10 publications

(6 citation statements)

References 15 publications

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“…A similar observation was reported for guinea-pigs by Kuosaite (1965), although others have been unable to repeat this (Linzell, 1963;Knight & Peaker, 1981). In mice, mammary development was reduced during gestation by hemihysterectomy, presumably as a result of decreased circulating levels of placental lactogen (Knight & Peaker, 1982b) and by short periods of fasting (Knight & Peaker, 1982c). In both cases compensatory growth of the gland occurred during early lactation, resulting in a normal milk yield.…”

Section: Methodssupporting

confidence: 79%

Compensatory changes in mammary development and function after hemimastectomy in lactating goats

Knight¹

1987

Reproduction

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Summary. Goats were hemimastectomized during Weeks 5 or 8 of lactation. The milk yield of the remaining gland (the test gland) usually increased in a compensatory fashion after the operation, although the degree of response varied from no response to a 50% increase. The glands of those goats that responded and received no further treatment maintained an increased milk yield for the duration of the lactation. Changes in the size and composition of the gland were investigated by a combination of udder volume and biopsy in some goats. Increases in both gross size and total DNA content (DNAt, a measure of cell number) were observed in all of these, although the timing of the response varied between individuals. Overall, cell population size was maintained for at least 18 weeks after hemimastectomy whereas in control (unoperated) goats DNA, decreased by 35% over a similar period.

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Section: Methodssupporting

confidence: 79%

Compensatory changes in mammary development and function after hemimastectomy in lactating goats

Knight¹

1987

Reproduction

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“…Because translation occurs on ribosomes and the majority of RNA in a cell is ribosomal, an increase in rRNA expression or RNA mass in cells is expected to result in faster rates of protein synthesis (Lobley, 1993). The onset of lactation in many species is associated with an increase in the RNA: DNA ratio of the mammary epithelium (Akers et al, 1981;Knight and Peaker, 1982), indicating a greater capacity for protein synthesis. The lactogenic hormone prolactin appears primarily responsible for inducing this increase in mammary RNA: DNA in rodents and ruminants alike (Baldwin and Martin, 1968;Akers et al, 1981;Forsyth and Lee, 1993).…”

Section: Cellular Abundance Of Translation Machinerymentioning

confidence: 99%

Symposium review: Amino acid uptake by the mammary glands: Where does the control lie?

Cant

Kim

Cieslar

et al. 2018

Journal of Dairy Science

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Milk protein yield responses to changes in the profile of essential amino acids absorbed by the gastrointestinal tract or circulating in blood plasma do not follow the classic limiting amino acid response, in part because of an ability of the mammary glands to modify their blood flow rate and net clearance of amino acids out of plasma. The hypothesis that mammary blood flow is locally regulated to maintain ATP balance accounts for observed changes in flow due to postruminal glucose, insulin, and essential amino acid (EAA) infusions. An additional hypothesis that net mammary uptakes of metabolites from blood are affected by perturbations in their respective arterial concentrations and the rate of mammary blood flow also appears to hold for the energy metabolites glucose, acetate, β-hydroxybutyrate, and fatty acids. However, net EAA uptakes by the mammary glands are poorly predicted by models considering arterial concentrations and blood flow rates only. Evidence points to intramammary protein synthesis and secretion as the determinant of net EAA uptake. The intracellular signaling network anchored by the mechanistic target of rapamycin complex 1 stands as an excellent candidate to explain nutritional effects on milk protein synthesis because it integrates information on physiological and nutritional state to affect protein synthesis and cell metabolism, growth, proliferation, and differentiation in many cell types. In mammary cells in vitro and in vivo, the mechanistic target of rapamycin complex 1, integrated stress response, and glycogen synthase kinase-3 networks that contribute to regulation of initiation of mRNA translation are responsive to acute changes in nutrient supply and EAA profile. However, after several days of postruminal infusion of balanced and imbalanced EAA profiles, these signaling networks do not appear to continue to account for changes in milk protein yields. Gene expression evidence suggests that regulation of components of the unfolded protein response that control biogenesis of the endoplasmic reticulum and differentiation of a secretory phenotype may contribute to effects of nutrition on milk protein yield. Connections between early signaling events and their long-term consequences should be sought.

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“…Breeding factors also have effects, particularly on the modulation of cell turnover in the mammary gland (Boutinaud and Jammes, 2004;Nørgaard et al, 2005). Mammary development during gestation and lactation is influenced by nutrition in many rodents and ruminants (Knight and Peaker, 1982). Experiments on early lactating rats showed that increasing feeding level during gestation led to an increase in cell proliferation and a decrease in apoptosis during late lactation (Kim et al, 1998;Moon and Park, 1999).…”

Section: Introductionmentioning

confidence: 99%

Effects of nutrient restriction on mammary cell turnover and mammary gland remodeling in lactating dairy cows

Dessauge

Lollivier

Ponchon

et al. 2011

Journal of Dairy Science

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The aim of this study was to investigate the effects of a severe nutrient restriction on mammary tissue morphology and remodeling, mammary epithelial cell (MEC) turnover and activity, and hormonal status in lactating dairy cows. We used 16 Holstein × Normande crossbred dairy cows, divided into 2 groups submitted to different feeding levels (basal and restricted) from 2 wk before calving to wk 11 postpartum. Restricted-diet cows had lower 11-wk average daily milk yield from calving to slaughter than did basal-diet cows (20.5 vs. 33.5 kg/d). Feed restriction decreased milk fat, protein, and lactose yields. Restriction also led to lower plasma insulin-like growth factor 1 and higher growth hormone concentrations. Restricted-diet cows had lighter mammary glands than did basal-diet cows. The total amount of DNA in the mammary gland and the size of the mammary acini were smaller in the restricted-diet group. Feed restriction had no significant effect on MEC proliferation at the time of slaughter but led to a higher level of apoptosis in the mammary gland. Gelatin zymography highlighted remodeling of the mammary extracellular matrix in restricted-diet cows. Udders from restricted-diet cows showed lower transcript expression of α-lactalbumin and kappa-casein. In conclusion, nutrient restriction resulted in lower milk yield in lactating dairy cows, partly due to modulation of MEC activity and a lower number of mammary cells. An association was found between feed restriction-induced changes in the growth hormone-insulin-like growth factor-1 axis and mammary epithelial cell dynamics.

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Effects of fasting during mid pregnancy or early lactation on mammary development and milk yield in mice

Cited by 10 publications

References 15 publications

Compensatory changes in mammary development and function after hemimastectomy in lactating goats

Compensatory changes in mammary development and function after hemimastectomy in lactating goats

Symposium review: Amino acid uptake by the mammary glands: Where does the control lie?

Effects of nutrient restriction on mammary cell turnover and mammary gland remodeling in lactating dairy cows

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