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Item Type: | Article |
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Title: | Abnormal neonatal sodium handling in skin precedes hypertension in the SAME rat |
Creators Name: | Mullins, L., Ivy, J., Ward, M., Tenstad, O., Wiig, H., Kitada, K., Manning, J., Rakova, N., Muller, D. and Mullins, J. |
Abstract: | We discovered high Na(+) and water content in the skin of newborn Sprague-Dawley rats, which reduced ~ 2.5-fold by 7 days of age, indicating rapid changes in extracellular volume (ECV). Equivalent changes in ECV post birth were also observed in C57Bl/6 J mice, with a fourfold reduction over 7 days, to approximately adult levels. This established the generality of increased ECV at birth. We investigated early sodium and water handling in neonates from a second rat strain, Fischer, and an Hsd11b2-knockout rat modelling the syndrome of apparent mineralocorticoid excess (SAME). Despite Hsd11b2(-/-) animals exhibiting lower skin Na(+) and water levels than controls at birth, they retained ~ 30% higher Na(+) content in their pelts at the expense of K(+) thereafter. Hsd11b2(-/-) neonates exhibited incipient hypokalaemia from 15 days of age and became increasingly polydipsic and polyuric from weaning. As with adults, they excreted a high proportion of ingested Na(+) through the kidney, (56.15 ± 8.21% versus control 34.15 ± 8.23%; n = 4; P < 0.0001), suggesting that changes in nephron electrolyte transporters identified in adults, by RNA-seq analysis, occur by 4 weeks of age. Our data reveal that Na(+) imbalance in the Hsd11b2(-/-) neonate leads to excess Na(+) storage in skin and incipient hypokalaemia, which, together with increased, glucocorticoid-induced Na(+) uptake in the kidney, then contribute to progressive, volume contracted, salt-sensitive hypertension. Skin Na(+) plays an important role in the development of SAME but, equally, may play a key physiological role at birth, supporting post-natal growth, as an innate barrier to infection or as a rudimentary kidney. |
Keywords: | Hsd11b2, Knockout, Hypertension, Newborn, Neonatal, Salt-sensitive, Skin, Animals, Mice, Rats |
Source: | Pflugers Archiv |
ISSN: | 0031-6768 |
Publisher: | Springer |
Volume: | 473 |
Number: | 6 |
Page Range: | 897-910 |
Date: | June 2021 |
Official Publication: | https://doi.org/10.1007/s00424-021-02582-7 |
PubMed: | View item in PubMed |
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