Glomerular filtration rate in weaned elephant seal pups during natural, long term fasts
Low urine output (< 200 mL/day) seen in weaned elephant seal pups is consistent with the physiological necessity of strict water conservation during periods of protracted, natural fasts. However, urine output represents only the difference between glomerular filtration rate (GFR) and tubular reab...
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Canadian Science Publishing
1989
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crcansciencepubl:10.1139/z89-251 2024-06-23T07:52:28+00:00 Glomerular filtration rate in weaned elephant seal pups during natural, long term fasts Pernia, S. D. Costa, D. P. Ortiz, C. Leo 1989 http://dx.doi.org/10.1139/z89-251 http://www.nrcresearchpress.com/doi/pdf/10.1139/z89-251 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 67, issue 7, page 1752-1756 ISSN 0008-4301 1480-3283 journal-article 1989 crcansciencepubl https://doi.org/10.1139/z89-251 2024-06-13T04:10:50Z Low urine output (< 200 mL/day) seen in weaned elephant seal pups is consistent with the physiological necessity of strict water conservation during periods of protracted, natural fasts. However, urine output represents only the difference between glomerular filtration rate (GFR) and tubular reabsorption and thus provides no information about the absolute magnitude of these parameters or their role in homeostatic regulation during the fast. We measured GFR, and extracellular volume (ECV) and estimated tubular reabsorption in seven pups that had been fasting > 6 weeks and in three others that had begun to feed in captivity using standard [ 3 H]inulin and [ 125 I]iothalamate clearance techniques. In fasting pups, GFR and ECV ranged from 78.9 to 135.2 mL/min and from 6.3 to 15.4 L, respectively. The GFR values are 59–91% [Formula: see text] of that predicted by standard body mass allometry. These data suggest that (i) low urine output is a consequence of tubular reabsorption rather than depressed GFR; (ii) a small but significant N and electrolyte load resulting from oxidation and reorganization of body tissue during development requires near "normal" renal function despite the potential loss of water from excess urine formation. Article in Journal/Newspaper Elephant Seal Canadian Science Publishing Canadian Journal of Zoology 67 7 1752 1756 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
Low urine output (< 200 mL/day) seen in weaned elephant seal pups is consistent with the physiological necessity of strict water conservation during periods of protracted, natural fasts. However, urine output represents only the difference between glomerular filtration rate (GFR) and tubular reabsorption and thus provides no information about the absolute magnitude of these parameters or their role in homeostatic regulation during the fast. We measured GFR, and extracellular volume (ECV) and estimated tubular reabsorption in seven pups that had been fasting > 6 weeks and in three others that had begun to feed in captivity using standard [ 3 H]inulin and [ 125 I]iothalamate clearance techniques. In fasting pups, GFR and ECV ranged from 78.9 to 135.2 mL/min and from 6.3 to 15.4 L, respectively. The GFR values are 59–91% [Formula: see text] of that predicted by standard body mass allometry. These data suggest that (i) low urine output is a consequence of tubular reabsorption rather than depressed GFR; (ii) a small but significant N and electrolyte load resulting from oxidation and reorganization of body tissue during development requires near "normal" renal function despite the potential loss of water from excess urine formation. |
format |
Article in Journal/Newspaper |
author |
Pernia, S. D. Costa, D. P. Ortiz, C. Leo |
spellingShingle |
Pernia, S. D. Costa, D. P. Ortiz, C. Leo Glomerular filtration rate in weaned elephant seal pups during natural, long term fasts |
author_facet |
Pernia, S. D. Costa, D. P. Ortiz, C. Leo |
author_sort |
Pernia, S. D. |
title |
Glomerular filtration rate in weaned elephant seal pups during natural, long term fasts |
title_short |
Glomerular filtration rate in weaned elephant seal pups during natural, long term fasts |
title_full |
Glomerular filtration rate in weaned elephant seal pups during natural, long term fasts |
title_fullStr |
Glomerular filtration rate in weaned elephant seal pups during natural, long term fasts |
title_full_unstemmed |
Glomerular filtration rate in weaned elephant seal pups during natural, long term fasts |
title_sort |
glomerular filtration rate in weaned elephant seal pups during natural, long term fasts |
publisher |
Canadian Science Publishing |
publishDate |
1989 |
url |
http://dx.doi.org/10.1139/z89-251 http://www.nrcresearchpress.com/doi/pdf/10.1139/z89-251 |
genre |
Elephant Seal |
genre_facet |
Elephant Seal |
op_source |
Canadian Journal of Zoology volume 67, issue 7, page 1752-1756 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/z89-251 |
container_title |
Canadian Journal of Zoology |
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67 |
container_issue |
7 |
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1752 |
op_container_end_page |
1756 |
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1802643773930340352 |