Swimming suppresses hepatic vitellogenesis in European female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver
Abstract Background When European silver eels (Anguilla anguilla) venture into the Atlantic Ocean for their 6,000 km semelparous spawning run to the Sargasso Sea, they are still in a prepubertal stage. Further sexual development appears to be blocked by dopaminergic inhibition of hypothalamus and pi...
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ftbiomed:oai:biomedcentral.com:1477-7827-8-27 2023-05-15T13:28:12+02:00 Swimming suppresses hepatic vitellogenesis in European female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver Palstra, Arjan P Schnabel, Denhi Nieveen, Maaike C Spaink, Herman P van den Thillart, Guido 2010-03-19 http://www.rbej.com/content/8/1/27 en eng BioMed Central Ltd. http://www.rbej.com/content/8/1/27 Copyright 2010 Palstra et al; licensee BioMed Central Ltd. Research 2010 ftbiomed 2010-04-03T23:28:04Z Abstract Background When European silver eels (Anguilla anguilla) venture into the Atlantic Ocean for their 6,000 km semelparous spawning run to the Sargasso Sea, they are still in a prepubertal stage. Further sexual development appears to be blocked by dopaminergic inhibition of hypothalamus and pituitary activity. Recently, we found that swimming for several weeks in freshwater stimulated the incorporation of fat droplets in the oocytes. So, it was hypothesized that long term swimming in seawater would release the inhibition further and would also stimulate the production of vitellogenin by the liver. Methods For this study a swim-flume was constructed to allow simulated migration of migratory female silver eels for 3 months (1,420 km) in natural seawater at 20 degrees C. Primers were designed for polymerase chain reactions to measure the mRNA expression of estrogen receptor 1 (esr1), vitellogenin1 (vtg1) and vitellogenin2 (vtg2) genes in the liver of European female silver eels. Results In comparison to resting eels, swimming eels showed a diminished expression of esr1, vtg1 and vtg2 in the liver. They also had lower plasma calcium (Ca; indicative of vitellogenin) levels in their blood. This showed that vitellogenesis is more strongly suppressed in swimming than in resting eels. However, when eels were subsequently stimulated by 3 weekly carp pituitary extract injections, the expression of the same genes and plasma levels of Ca strongly increased in both groups to similar levels, thus equalizing the initial differences between resting and swimming. Conclusions It is concluded that vitellogenesis remains suppressed during resting and even more during swimming. The fact that swimming stimulates fat deposition in the oocytes but suppresses vitellogenesis indicates that these events are separated in nature and occur sequentially. Swimming-suppressed vitellogenesis may imply that in nature eels undergo vitellogenesis and final maturation near or at the spawning grounds. Other/Unknown Material Anguilla anguilla BioMed Central |
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Open Polar |
collection |
BioMed Central |
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ftbiomed |
language |
English |
description |
Abstract Background When European silver eels (Anguilla anguilla) venture into the Atlantic Ocean for their 6,000 km semelparous spawning run to the Sargasso Sea, they are still in a prepubertal stage. Further sexual development appears to be blocked by dopaminergic inhibition of hypothalamus and pituitary activity. Recently, we found that swimming for several weeks in freshwater stimulated the incorporation of fat droplets in the oocytes. So, it was hypothesized that long term swimming in seawater would release the inhibition further and would also stimulate the production of vitellogenin by the liver. Methods For this study a swim-flume was constructed to allow simulated migration of migratory female silver eels for 3 months (1,420 km) in natural seawater at 20 degrees C. Primers were designed for polymerase chain reactions to measure the mRNA expression of estrogen receptor 1 (esr1), vitellogenin1 (vtg1) and vitellogenin2 (vtg2) genes in the liver of European female silver eels. Results In comparison to resting eels, swimming eels showed a diminished expression of esr1, vtg1 and vtg2 in the liver. They also had lower plasma calcium (Ca; indicative of vitellogenin) levels in their blood. This showed that vitellogenesis is more strongly suppressed in swimming than in resting eels. However, when eels were subsequently stimulated by 3 weekly carp pituitary extract injections, the expression of the same genes and plasma levels of Ca strongly increased in both groups to similar levels, thus equalizing the initial differences between resting and swimming. Conclusions It is concluded that vitellogenesis remains suppressed during resting and even more during swimming. The fact that swimming stimulates fat deposition in the oocytes but suppresses vitellogenesis indicates that these events are separated in nature and occur sequentially. Swimming-suppressed vitellogenesis may imply that in nature eels undergo vitellogenesis and final maturation near or at the spawning grounds. |
format |
Other/Unknown Material |
author |
Palstra, Arjan P Schnabel, Denhi Nieveen, Maaike C Spaink, Herman P van den Thillart, Guido |
spellingShingle |
Palstra, Arjan P Schnabel, Denhi Nieveen, Maaike C Spaink, Herman P van den Thillart, Guido Swimming suppresses hepatic vitellogenesis in European female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver |
author_facet |
Palstra, Arjan P Schnabel, Denhi Nieveen, Maaike C Spaink, Herman P van den Thillart, Guido |
author_sort |
Palstra, Arjan P |
title |
Swimming suppresses hepatic vitellogenesis in European female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver |
title_short |
Swimming suppresses hepatic vitellogenesis in European female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver |
title_full |
Swimming suppresses hepatic vitellogenesis in European female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver |
title_fullStr |
Swimming suppresses hepatic vitellogenesis in European female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver |
title_full_unstemmed |
Swimming suppresses hepatic vitellogenesis in European female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver |
title_sort |
swimming suppresses hepatic vitellogenesis in european female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver |
publisher |
BioMed Central Ltd. |
publishDate |
2010 |
url |
http://www.rbej.com/content/8/1/27 |
genre |
Anguilla anguilla |
genre_facet |
Anguilla anguilla |
op_relation |
http://www.rbej.com/content/8/1/27 |
op_rights |
Copyright 2010 Palstra et al; licensee BioMed Central Ltd. |
_version_ |
1766402725309841408 |