Epidermal Growth Factor and Parathyroid Hormone-related Peptide mRNA in the Mammary Gland and their Concentrations in Milk: Effects of Postpartum Hypoxia in Lactating Rats

Bruder, Eric D.; Hoof, Johan Van; Young, J. B.; Raff, Hershel

doi:10.1055/s-2008-1058101

Cited by 11 publications

(11 citation statements)

References 58 publications

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“…Real-time PCR data are presented as the number of cycles needed to cross a predetermined cycle threshold (C t), as previously published (6). The Ct value is set at a point at which an increase in fluorescence (and therefore cDNA concentration) is exponential.…”

Section: Methodsmentioning

confidence: 99%

Development of the ACTH and corticosterone response to acute hypoxia in the neonatal rat

Bruder¹,

Taylor²,

Kamer³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

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Acute episodes of severe hypoxia are among the most common stressors in neonates. An understanding of the development of the physiological response to acute hypoxia will help improve clinical interventions. The present study measured ACTH and corticosterone responses to acute, severe hypoxia (8% inspired O(2) for 4 h) in neonatal rats at postnatal days (PD) 2, 5, and 8. Expression of specific hypothalamic, anterior pituitary, and adrenocortical mRNAs was assessed by real-time PCR, and expression of specific proteins in isolated adrenal mitochondria from adrenal zona fascisulata/reticularis was assessed by immunoblot analyses. Oxygen saturation, heart rate, and body temperature were also measured. Exposure to 8% O(2) for as little as 1 h elicited an increase in plasma corticosterone in all age groups studied, with PD2 pups showing the greatest response ( approximately 3 times greater than PD8 pups). Interestingly, the ACTH response to hypoxia was absent in PD2 pups, while plasma ACTH nearly tripled in PD8 pups. Analysis of adrenal mRNA expression revealed a hypoxia-induced increase in Ldlr mRNA at PD2, while both Ldlr and Star mRNA were increased at PD8. Acute hypoxia decreased arterial O(2) saturation (SPo(2)) to approximately 80% and also decreased body temperature by 5-6 degrees C. The hypoxic thermal response may contribute to the ACTH and corticosterone response to decreases in oxygen. The present data describe a developmentally regulated, differential corticosterone response to acute hypoxia, shifting from ACTH independence in early life (PD2) to ACTH dependence less than 1 wk later (PD8).

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Section: Methodsmentioning

confidence: 99%

Development of the ACTH and corticosterone response to acute hypoxia in the neonatal rat

Bruder¹,

Taylor²,

Kamer³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

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“…In order to study hypoxia in the neonate without altering maternal physiology due to exposure to hypoxia (Bruder et al. ), the normoxic control group for our model separates the neonatal rat pups from their lactating dam (Bruder et al. ; Guenther et al.…”

Section: Introductionmentioning

confidence: 99%

Sex differences in adult rat insulin and glucose responses to arginine: programming effects of neonatal separation, hypoxia, and hypothermia

et al. 2016

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Acute neonatal hypoxia, a common stressor, causes a spontaneous decrease in body temperature which may be protective. There is consensus that hypothermia should be prevented during acute hypoxia in the human neonate; however, this may be an additional stress with negative consequences. We hypothesize that maintaining body temperature during hypoxia in the first week of postnatal life alters the subsequent insulin, glucose, and glucagon secretion in adult rats. Rat pups were separated from their dam daily from postnatal days (PD) 2–6 for the following 90 min experimental treatments: (1) normoxic separation (control), (2) hypoxia (8% O2) allowing spontaneous hypothermia, (3) normoxic hypothermia with external cold, and (4) exposure to 8% O2 while maintaining body temperature using external heat. An additional normoxic non‐separated control group was performed to determine if separation per se changed the adult phenotype. Plasma insulin, glucose, and glucagon responses to arginine stimulation were evaluated from PD105 to PD133. Maternal separation (compared to non‐separated neonates) had more pronounced effects on the adult response to arginine compared to the hypoxic, hypothermic, and hypoxic‐isothermic neonatal treatments. Adult males exposed to neonatal maternal separation had augmented insulin and glucose responses to arginine compared to unseparated controls. Additionally, neonatal treatment had a significant effect on body weight gain; adults exposed to neonatal maternal separation were significantly heavier. Female adults had significantly smaller insulin and glucose responses to arginine regardless of neonatal treatment. Neonatal maternal separation during the first week of life significantly altered adult beta‐cell function in a sexually dimorphic manner.

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“…The inverse correlation observed between TGF-β2 levels in milk and plasma could suggest that the passage of TGF-β2 from blood to milk in rats is not the main pathway as described in humans [ 77 ]. EGF was not detected in rat plasma, and the presence of EGF mRNA transcripts was described in rats’ mammary gland, thus suggesting that this gland could be the origin of milk EGF [ 78 ]. However, it is demonstrated in other species that maternal blood, rather than the mammary gland, appears to be the main source of EGF in breast milk [ 79 ].…”

Section: Discussionmentioning

confidence: 99%

Rat Milk and Plasma Immunological Profile throughout Lactation

et al. 2021

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The composition of bioactive factors with immune activity in human breast milk is widely studied. However, the knowledge on rat milk immune factors during the whole lactation period is still scarce. This study aimed to analyze rat breast milk’s immunoglobulin (Ig) content and some critical adipokines and growth factors throughout the lactation period, and to assess relationships with corresponding plasma levels. During lactation, milk concentration of the transforming growth factor (TGF)-β2 and -β3 showed a punctual increase in the first week, whereas adiponectin and leptin remained stable. In the second period of lactation (d14–21), despite the increase in the milk epidermal growth factor (EGF), a decrease in fibroblast growth factor 21 (FGF21) was detected at day 21. Milk IgA concentration had a progressive increase during lactation, while no significant changes were found in IgM and IgG. Regarding plasma levels, a decrease in all studied adipokines was observed in the second period of lactation, with the exception of IgA and TGF-β1, which reached their highest values at the end of the study. A positive correlation in IgM, IgG, and adipokine concentration was detected between milk and plasma compartments. In summary, the changes in the pattern of these bioactive compounds in rat milk and plasma and their relationships during lactation are established.

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Epidermal Growth Factor and Parathyroid Hormone-related Peptide mRNA in the Mammary Gland and their Concentrations in Milk: Effects of Postpartum Hypoxia in Lactating Rats

Cited by 11 publications

References 58 publications

Development of the ACTH and corticosterone response to acute hypoxia in the neonatal rat

Development of the ACTH and corticosterone response to acute hypoxia in the neonatal rat

Sex differences in adult rat insulin and glucose responses to arginine: programming effects of neonatal separation, hypoxia, and hypothermia

Rat Milk and Plasma Immunological Profile throughout Lactation

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