Glucocorticoid‐Receptor Mediated Signaling Regulates Lipolysis in Northern Elephant Seal Pups
Northern elephant seals (NES) experience prolonged 2–3 month fasting periods, relying primarily on the oxidation of fatty acids to meet their energetic needs (RQ=0.71). Although fasting periods are characterized by an increase in circulating cortisol (F) and non‐esterified fatty acids (NEFA's),...
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crwiley:10.1096/fasebj.2018.32.1_supplement.861.10 2024-06-02T08:06:01+00:00 Glucocorticoid‐Receptor Mediated Signaling Regulates Lipolysis in Northern Elephant Seal Pups Juarez, Pablo Vasquez‐Medina, Jose Pablo Lee, Debby Croker, Daniel E. Ortiz, Rudy 2018 http://dx.doi.org/10.1096/fasebj.2018.32.1_supplement.861.10 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor The FASEB Journal volume 32, issue S1 ISSN 0892-6638 1530-6860 journal-article 2018 crwiley https://doi.org/10.1096/fasebj.2018.32.1_supplement.861.10 2024-05-03T11:45:29Z Northern elephant seals (NES) experience prolonged 2–3 month fasting periods, relying primarily on the oxidation of fatty acids to meet their energetic needs (RQ=0.71). Although fasting periods are characterized by an increase in circulating cortisol (F) and non‐esterified fatty acids (NEFA's), the functional relevance such increase in cortisol in NES is not defined. We hypothesized that F lipolysis is regulated through glucocorticoid receptor signaling (GR) in NES. The contributions of F and the GR were assessed by exogenous infusions of ACTH and/or concurrent blockade of the GR in the following groups: (1) untreated control, (2) ACTH (80 units intramuscular injection (IM)) and (3) ACTH + GR blocker (RU486) (80 units IM + 400mg RU486 in time release pellets). Plasma, and adipose and muscle biopsies were collected at days 0 (T0; immediately prior to infusion) and 6 (T6). Mean plasma NEFA levels increased 38% (0.84 ± 0.13 vs 1.16 ± 0.06mM) from T0 to T6 with ACTH infusion suggesting glucocorticoids contribute to increased lipolysis. ACTH infusion increased mean adipose HSP90 expression by 92%±18.2 while decreasing mean muscle HSP90 expression by 39%±14.5 from T0 to T6 suggesting that HSP90 may participate in GR‐mediated lipolysis in adipose while contributing to conserving lipid sources in muscle. Mean muscle CD36 expression decreased 46%±12.2 from T0 to T6 with ACTH infusion suggesting that there is a reduced intake of NEFA's by skeletal muscle, contributing to increased circulating NEFAs during lipolysis. These data suggest that the fasting‐associated increase in GR signaling is imperative for sustaining elevated levels of lipolysis during the post weaning fast, and is dependent upon the functional role of cortisol and HSP90. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal . Article in Journal/Newspaper Elephant Seal Elephant Seals Wiley Online Library Nes ENVELOPE(7.634,7.634,62.795,62.795) Nes’ ENVELOPE(44.681,44.681,66.600,66.600) The FASEB Journal 32 S1 |
institution |
Open Polar |
collection |
Wiley Online Library |
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crwiley |
language |
English |
description |
Northern elephant seals (NES) experience prolonged 2–3 month fasting periods, relying primarily on the oxidation of fatty acids to meet their energetic needs (RQ=0.71). Although fasting periods are characterized by an increase in circulating cortisol (F) and non‐esterified fatty acids (NEFA's), the functional relevance such increase in cortisol in NES is not defined. We hypothesized that F lipolysis is regulated through glucocorticoid receptor signaling (GR) in NES. The contributions of F and the GR were assessed by exogenous infusions of ACTH and/or concurrent blockade of the GR in the following groups: (1) untreated control, (2) ACTH (80 units intramuscular injection (IM)) and (3) ACTH + GR blocker (RU486) (80 units IM + 400mg RU486 in time release pellets). Plasma, and adipose and muscle biopsies were collected at days 0 (T0; immediately prior to infusion) and 6 (T6). Mean plasma NEFA levels increased 38% (0.84 ± 0.13 vs 1.16 ± 0.06mM) from T0 to T6 with ACTH infusion suggesting glucocorticoids contribute to increased lipolysis. ACTH infusion increased mean adipose HSP90 expression by 92%±18.2 while decreasing mean muscle HSP90 expression by 39%±14.5 from T0 to T6 suggesting that HSP90 may participate in GR‐mediated lipolysis in adipose while contributing to conserving lipid sources in muscle. Mean muscle CD36 expression decreased 46%±12.2 from T0 to T6 with ACTH infusion suggesting that there is a reduced intake of NEFA's by skeletal muscle, contributing to increased circulating NEFAs during lipolysis. These data suggest that the fasting‐associated increase in GR signaling is imperative for sustaining elevated levels of lipolysis during the post weaning fast, and is dependent upon the functional role of cortisol and HSP90. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal . |
format |
Article in Journal/Newspaper |
author |
Juarez, Pablo Vasquez‐Medina, Jose Pablo Lee, Debby Croker, Daniel E. Ortiz, Rudy |
spellingShingle |
Juarez, Pablo Vasquez‐Medina, Jose Pablo Lee, Debby Croker, Daniel E. Ortiz, Rudy Glucocorticoid‐Receptor Mediated Signaling Regulates Lipolysis in Northern Elephant Seal Pups |
author_facet |
Juarez, Pablo Vasquez‐Medina, Jose Pablo Lee, Debby Croker, Daniel E. Ortiz, Rudy |
author_sort |
Juarez, Pablo |
title |
Glucocorticoid‐Receptor Mediated Signaling Regulates Lipolysis in Northern Elephant Seal Pups |
title_short |
Glucocorticoid‐Receptor Mediated Signaling Regulates Lipolysis in Northern Elephant Seal Pups |
title_full |
Glucocorticoid‐Receptor Mediated Signaling Regulates Lipolysis in Northern Elephant Seal Pups |
title_fullStr |
Glucocorticoid‐Receptor Mediated Signaling Regulates Lipolysis in Northern Elephant Seal Pups |
title_full_unstemmed |
Glucocorticoid‐Receptor Mediated Signaling Regulates Lipolysis in Northern Elephant Seal Pups |
title_sort |
glucocorticoid‐receptor mediated signaling regulates lipolysis in northern elephant seal pups |
publisher |
Wiley |
publishDate |
2018 |
url |
http://dx.doi.org/10.1096/fasebj.2018.32.1_supplement.861.10 |
long_lat |
ENVELOPE(7.634,7.634,62.795,62.795) ENVELOPE(44.681,44.681,66.600,66.600) |
geographic |
Nes Nes’ |
geographic_facet |
Nes Nes’ |
genre |
Elephant Seal Elephant Seals |
genre_facet |
Elephant Seal Elephant Seals |
op_source |
The FASEB Journal volume 32, issue S1 ISSN 0892-6638 1530-6860 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1096/fasebj.2018.32.1_supplement.861.10 |
container_title |
The FASEB Journal |
container_volume |
32 |
container_issue |
S1 |
_version_ |
1800750898742296576 |