Changes in luteinizing hormone secretion after estradiol treatment in prepubertal Nelore heifers
Main Author: | |
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Publication Date: | 2011 |
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Format: | Article |
Language: | eng |
Source: | Repositório Institucional da UNESP |
Download full: | http://hdl.handle.net/11449/226420 |
Summary: | Changes in luteinizing hormone (LH) secretion after 17β-estradiol (E 2) injection were evaluated during sexual maturation in 10 prepubertal Nelore heifers. Heifers were divided into 2 groups: intact (I) and ovariectomized (OVX). 17β-estradiol (2 μg/kg) was administered to both groups at 10, 13, and 17 mo of age. Only at 10 mo of age was there a greater mean LH concentration in OVX heifers (1.33 ± 0.29 ng/mL) compared with the I group (0.57 ± 0.15 ng/mL). At 13 and 17 mo of age there was no significant difference between the 2 groups in any of the evaluated variables (number of peaks, total peak area, greatest peak area, and time to greatest peak occurrence). This suggests a decrease in negative E 2 feedback associated with an increase in positive feedback to LH secretion during sexual maturation, and these were likely the key factors that determined the time of first ovulation in Nelore heifers. |
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Changes in luteinizing hormone secretion after estradiol treatment in prepubertal Nelore heifersChanges in luteinizing hormone (LH) secretion after 17β-estradiol (E 2) injection were evaluated during sexual maturation in 10 prepubertal Nelore heifers. Heifers were divided into 2 groups: intact (I) and ovariectomized (OVX). 17β-estradiol (2 μg/kg) was administered to both groups at 10, 13, and 17 mo of age. Only at 10 mo of age was there a greater mean LH concentration in OVX heifers (1.33 ± 0.29 ng/mL) compared with the I group (0.57 ± 0.15 ng/mL). At 13 and 17 mo of age there was no significant difference between the 2 groups in any of the evaluated variables (number of peaks, total peak area, greatest peak area, and time to greatest peak occurrence). This suggests a decrease in negative E 2 feedback associated with an increase in positive feedback to LH secretion during sexual maturation, and these were likely the key factors that determined the time of first ovulation in Nelore heifers.Paulista Extreme West Development Regional Pole-APTA (Pólo Extremo Oeste), Av. Alcides Fagundes Chagas, 122, 16055-565, Araçatuba, São PauloFUNEP, Penápolis, São PauloDepartment of Clinics, Surgery and Animal Reproduction (DCCRA) Univ Estadual Paulista (UNESP), Araçatuba, São PauloDepartment of Production and Animal Health (DAPSA) UNESP, Araçatuba, São PauloDepartment of Clinics, Surgery and Animal Reproduction (DCCRA) Univ Estadual Paulista (UNESP), Araçatuba, São PauloDepartment of Production and Animal Health (DAPSA) UNESP, Araçatuba, São PauloPaulista Extreme West Development Regional Pole-APTA (Pólo Extremo Oeste)FUNEPUniversidade Estadual Paulista (UNESP)Cardoso, DanielGuerra, Fábio F.Peiró, Juliana R. [UNESP]Perri, Silvia H.V. [UNESP]Nogueira, Guilherme P. [UNESP]2022-04-28T22:49:08Z2022-04-28T22:49:08Z2011-07-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article237-240Canadian Journal of Veterinary Research, v. 75, n. 3, p. 237-240, 2011.0830-9000http://hdl.handle.net/11449/2264202-s2.0-79960211491Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengCanadian Journal of Veterinary Researchinfo:eu-repo/semantics/openAccess2022-04-28T22:49:08Zoai:repositorio.unesp.br:11449/226420Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462022-04-28T22:49:08Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Changes in luteinizing hormone secretion after estradiol treatment in prepubertal Nelore heifers |
title |
Changes in luteinizing hormone secretion after estradiol treatment in prepubertal Nelore heifers |
spellingShingle |
Changes in luteinizing hormone secretion after estradiol treatment in prepubertal Nelore heifers Cardoso, Daniel |
title_short |
Changes in luteinizing hormone secretion after estradiol treatment in prepubertal Nelore heifers |
title_full |
Changes in luteinizing hormone secretion after estradiol treatment in prepubertal Nelore heifers |
title_fullStr |
Changes in luteinizing hormone secretion after estradiol treatment in prepubertal Nelore heifers |
title_full_unstemmed |
Changes in luteinizing hormone secretion after estradiol treatment in prepubertal Nelore heifers |
title_sort |
Changes in luteinizing hormone secretion after estradiol treatment in prepubertal Nelore heifers |
author |
Cardoso, Daniel |
author_facet |
Cardoso, Daniel Guerra, Fábio F. Peiró, Juliana R. [UNESP] Perri, Silvia H.V. [UNESP] Nogueira, Guilherme P. [UNESP] |
author_role |
author |
author2 |
Guerra, Fábio F. Peiró, Juliana R. [UNESP] Perri, Silvia H.V. [UNESP] Nogueira, Guilherme P. [UNESP] |
author2_role |
author author author author |
dc.contributor.none.fl_str_mv |
Paulista Extreme West Development Regional Pole-APTA (Pólo Extremo Oeste) FUNEP Universidade Estadual Paulista (UNESP) |
dc.contributor.author.fl_str_mv |
Cardoso, Daniel Guerra, Fábio F. Peiró, Juliana R. [UNESP] Perri, Silvia H.V. [UNESP] Nogueira, Guilherme P. [UNESP] |
description |
Changes in luteinizing hormone (LH) secretion after 17β-estradiol (E 2) injection were evaluated during sexual maturation in 10 prepubertal Nelore heifers. Heifers were divided into 2 groups: intact (I) and ovariectomized (OVX). 17β-estradiol (2 μg/kg) was administered to both groups at 10, 13, and 17 mo of age. Only at 10 mo of age was there a greater mean LH concentration in OVX heifers (1.33 ± 0.29 ng/mL) compared with the I group (0.57 ± 0.15 ng/mL). At 13 and 17 mo of age there was no significant difference between the 2 groups in any of the evaluated variables (number of peaks, total peak area, greatest peak area, and time to greatest peak occurrence). This suggests a decrease in negative E 2 feedback associated with an increase in positive feedback to LH secretion during sexual maturation, and these were likely the key factors that determined the time of first ovulation in Nelore heifers. |
publishDate |
2011 |
dc.date.none.fl_str_mv |
2011-07-01 2022-04-28T22:49:08Z 2022-04-28T22:49:08Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
Canadian Journal of Veterinary Research, v. 75, n. 3, p. 237-240, 2011. 0830-9000 http://hdl.handle.net/11449/226420 2-s2.0-79960211491 |
identifier_str_mv |
Canadian Journal of Veterinary Research, v. 75, n. 3, p. 237-240, 2011. 0830-9000 2-s2.0-79960211491 |
url |
http://hdl.handle.net/11449/226420 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Canadian Journal of Veterinary Research |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
237-240 |
dc.source.none.fl_str_mv |
Scopus reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
|
_version_ |
1799964544009764864 |