Changes of Plasma Osmotic Pressure during Lactation in Rats.

Suzuki, Kazuyuki; Hirose, Hisashi; Hokao, Ryoji; Takemura, Naoyuki; Motoyoshi, Shigekatsu

doi:10.1292/jvms.55.561

Cited by 22 publications

(22 citation statements)

References 19 publications

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“…One potential explanation for the contrasting trends is that any elevation in damage in the liver might be diluted by hypertrophy of the liver during lactation (Kennedy et al, 1958;Speakman and McQueenie, 1996;Johnson et al, 2001b;Król et al, 2003). Although there is also a large increase in blood volume during lactation, this appears to be mostly added water, rather than greater numbers of cells (Suzuki et al, 1993). However, differential hypertrophy seems an unlikely explanation because the reduction in damage was not observed in all markers (protein thiols, for example, were unchanged).…”

Section: Discussionmentioning

confidence: 99%

Effects of reproduction on immuno-suppression and oxidative damage, and hence support or otherwise for their roles as mechanisms underpinning life history trade-offs, are tissue and assay dependent

Yang

Wang

et al. 2013

Journal of Experimental Biology

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SUMMARYLife history parameters appear to be traded off against each other, but the physiological mechanisms involved remain unclear. One hypothesis is that potentially energetically costly processes such as immune function and protection from oxidative stress may be compromised during reproductive attempts because of selective resource allocation. Lower temperatures also impose energy costs, and hence allocation decisions might be more pronounced when animals are forced to reproduce in the cold. Here, we experimentally tested whether reproduction at different ambient temperatures was associated with elevated oxidative stress and suppressed immune function in Mongolian gerbils (Meriones unguiculatus). Using a variety of different markers for both immune function and oxidative stress, we found that some measures of immune function (serum bactericidal capacity and size of the thymus) were significantly suppressed, while some measures of oxidative protection [serum superoxide dismutase (SOD) activity and glutathione peroxidase (GPx) activity] were also reduced, and a marker of oxidative damage (protein carbonyls in serum) was increased in lactating compared with non-reproductive gerbils. These changes were in line with the selective resource allocation predictions. However, the phytohaemagglutinin response and serum total immunoglobulin (IgG) were not suppressed, and other markers of oxidative damage [malondialdehyde (MDA) (TBARS) and protein carbonyls in the liver] were actually lower in lactating compared with non-reproductive gerbils, consistent with increased levels of SOD activity and total antioxidant capacity in the liver. These latter changes were opposite of the expectations based on resource allocation. Furthermore, other measures of protection (GPx levels in the liver and protein thiols in both serum and liver) and damage [MDA (TBARS) in serum] were unrelated to reproductive status. Ambient temperature differences did not impact on these patterns. Collectively, our results indicated that the inferred effects of reproduction on immunosuppression and oxidative damage, and hence support or otherwise for particular physiological mechanisms that underpin life history trade-offs, are critically dependent on the exact markers and tissues used. This may be because during reproduction individuals selectively allocate protection to some key tissues, but sacrifice protection of others. Supplementary material available online at

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Section: Discussionmentioning

confidence: 99%

Effects of reproduction on immuno-suppression and oxidative damage, and hence support or otherwise for their roles as mechanisms underpinning life history trade-offs, are tissue and assay dependent

Yang

Wang

et al. 2013

Journal of Experimental Biology

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“…Several physiological conditions are changed during lactation that have been well documented in rats and directly relate to mice, as their lactation period is of the same length. A decrease in total plasma proteins due to increased blood volume, cardiac output, and blood flow to certain tissues, such as the mammary gland, has been reported in rats [26,27]. Elevated blood volume is due to increased plasma volume [27].…”

Section: Discussionmentioning

confidence: 99%

“…A decrease in total plasma proteins due to increased blood volume, cardiac output, and blood flow to certain tissues, such as the mammary gland, has been reported in rats [26,27]. Elevated blood volume is due to increased plasma volume [27]. Milk yield (g/h) in rats was reported to reach its peak by PND10 [27] and the rat mammary gland reaches its maximum size (as % body weight) by PND15 [26], with a steep rise in size from PND5–15.…”

Section: Discussionmentioning

confidence: 99%

Analysis of PFOA in dosed CD-1 mice. Part 2: Disposition of PFOA in tissues and fluids from pregnant and lactating mice and their pups

Fenton

Reiner

Nakayama

et al. 2009

Reproductive Toxicology

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Previous studies in mice with multiple gestational exposures to perfluorooctanoic acid (PFOA) demonstrate numerous dose dependent growth and developmental effects which appeared to worsen if offspring exposed in utero nursed from PFOA-exposed dams. To evaluate the disposition of PFOA in the pregnant and lactating dam and her offspring, time-pregnant CD-1 mice received a single 0, 0.1, 1, or 5 mg PFOA/kg BW dose (n = 25/dose group) by gavage on gestation day 17. Maternal and pup fluids and tissues were collected over time. Pups exhibited significantly higher serum PFOA concentrations than their respective dams, and their body burden increased after birth until at least postnatal day 8, regardless of dose. The distribution of milk:serum PFOA varied by dose and time, but was typically in excess of 0.20. These data suggest that milk is a substantial PFOA exposure route in mice and should be considered in risk assessment modeling designs for this compound.

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“…Of course, in addition to actually ingesting and digesting the extra food, the resulting nutrients must then be processed and transported throughout the body for use in peripheral areas (e.g. milk production by the mammary glands; Hammond et al, 1994), hence lactation is also associated with increased liver mass (present study ;Hammond et al, 1994) and blood volume (Suzuki et al, 1993(Suzuki et al, , 2000.…”

Section: Morphological Plasticity and Body Composition Lactationmentioning

confidence: 92%

Morphological plasticity varies with duration of infection: evidence from lactating and virgin wild-derived house mice (Mus musculus) infected with an intestinal parasite (Heligmosomoides polygyrus;Nematoda)

Kristan

Hammond

2004

Journal of Experimental Biology

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With chronic parasite infection, host response to the parasite may change throughout the duration of the infection as the host progresses from the acute to the chronic phase. We investigated the effects of parasite infection ranging in duration from 30 to 120·days on host morphology both alone and in combination with lactation by using captive wild-derived house mice (Mus musculus) experimentally infected with a naturally occurring intestinal nematode (Heligmosomoides polygyrus). We found that some changes in host morphology were greatest at 30-60·days post-infection (e.g. spleen mass) followed by a decline towards the control state whereas other morphological changes were greatest at 90-120·days postinfection (e.g. small intestine mass) after a relatively steady increase with infection duration. For all infection durations, the morphological responses to parasite infection were similar for virgin and lactating mice (except for lean body mass). After accounting for changes in body mass with lactation, lactating mice increased organs of the gastrointestinal tract as well as liver and kidney but had less body fat than virgin mice. This is the first study to demonstrate that morphological plasticity of mice parasitized by H. polygyrus varies with infection duration and that this variation is generally similar for lactating and virgin mice.

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Changes of Plasma Osmotic Pressure during Lactation in Rats.

Cited by 22 publications

References 19 publications

Effects of reproduction on immuno-suppression and oxidative damage, and hence support or otherwise for their roles as mechanisms underpinning life history trade-offs, are tissue and assay dependent

Effects of reproduction on immuno-suppression and oxidative damage, and hence support or otherwise for their roles as mechanisms underpinning life history trade-offs, are tissue and assay dependent

Analysis of PFOA in dosed CD-1 mice. Part 2: Disposition of PFOA in tissues and fluids from pregnant and lactating mice and their pups

Morphological plasticity varies with duration of infection: evidence from lactating and virgin wild-derived house mice (Mus musculus) infected with an intestinal parasite (Heligmosomoides polygyrus;Nematoda)

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