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The effects of intravenous, glucose versus saline on ovarian follicles and their levels of some mediators of insulin signalling
BACKGROUND: A short-term increase in food intake and specifically dietary energy can stimulate folliculogenesis and increase ovulation rate in ewes. The mechanism appears to involve the insulin-glucose metabolic system and its interaction with FSH signalling pathways in the granulosa cells of ovaria...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4417278/ https://www.ncbi.nlm.nih.gov/pubmed/25604903 http://dx.doi.org/10.1186/1477-7827-13-6 |
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author | Scaramuzzi, Rex John Zouaïdi, Nesrine Menassol, Jean-Baptiste Dupont, Joëlle |
author_facet | Scaramuzzi, Rex John Zouaïdi, Nesrine Menassol, Jean-Baptiste Dupont, Joëlle |
author_sort | Scaramuzzi, Rex John |
collection | PubMed |
description | BACKGROUND: A short-term increase in food intake and specifically dietary energy can stimulate folliculogenesis and increase ovulation rate in ewes. The mechanism appears to involve the insulin-glucose metabolic system and its interaction with FSH signalling pathways in the granulosa cells of ovarian follicles. This experiment was designed to investigate the interaction between these two systems in the granulosa cells of ovarian follicles. METHODS: Thirty six Ile-de-France ewes were used in this controlled experiment to study the effects of intravenous glucose on folliculogenesis. Eighteen ewes were infused with glucose (10 mM/h for 72 h) from day 8 of the oestrous cycle, while the others (controls) received saline. Ovaries were collected when the infusions ended (luteal phase) or 30 h later and after a luteolytic dose of a PGF(2α) analogue (follicular phase). Follicles were dissected and granulosa cells and follicular fluid harvested. The blood concentrations of glucose, insulin, oestradiol and FSH were monitored over the experiment. The levels of Aromatase P(450) and of the phosphorylated and non-phosphorylated forms of Akt, AMPK and ERK in granulosa cells and the concentration of oestradiol in follicular fluid, were determined. RESULTS: Glucose increased the circulating concentration of glucose (P < 0.05) and insulin (P < 0.05). It also increased the total number of follicles >1.0 mm in diameter (P < 0.05) and small (P < 0.05) follicles (>1.0 to 2.0 mm in diameter) but not medium (>2.0 to 3.5 mm in diameter) or large (>3.5 mm in diameter) follicles. Glucose decreased circulating oestradiol (P < 0.05) but not that of FSH or progesterone. Glucose reduced aromatase P(450) (P < 0.05) and decreased the phosphorylation of Akt (P < 0.05), ERK (P < 0.05) and AMPK (P < 0.05) in granulosa cells from oestrogenic follicles. The level of Aromatase P(450) was greatest in large oestrogenic follicles and the phosphorylation of Akt (P < 0.05), ERK (P < 0.05) and AMPK (P < 0.05) was lower in small follicles compared to medium and large follicles. CONCLUSIONS: These data suggest that the effect of glucose in small follicles is a direct action of glucose that increases the number of small follicles while the effect of glucose in oestrogenic follicles is an indirect insulin-mediated action. |
format | Online Article Text |
id | pubmed-4417278 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-44172782015-05-03 The effects of intravenous, glucose versus saline on ovarian follicles and their levels of some mediators of insulin signalling Scaramuzzi, Rex John Zouaïdi, Nesrine Menassol, Jean-Baptiste Dupont, Joëlle Reprod Biol Endocrinol Research BACKGROUND: A short-term increase in food intake and specifically dietary energy can stimulate folliculogenesis and increase ovulation rate in ewes. The mechanism appears to involve the insulin-glucose metabolic system and its interaction with FSH signalling pathways in the granulosa cells of ovarian follicles. This experiment was designed to investigate the interaction between these two systems in the granulosa cells of ovarian follicles. METHODS: Thirty six Ile-de-France ewes were used in this controlled experiment to study the effects of intravenous glucose on folliculogenesis. Eighteen ewes were infused with glucose (10 mM/h for 72 h) from day 8 of the oestrous cycle, while the others (controls) received saline. Ovaries were collected when the infusions ended (luteal phase) or 30 h later and after a luteolytic dose of a PGF(2α) analogue (follicular phase). Follicles were dissected and granulosa cells and follicular fluid harvested. The blood concentrations of glucose, insulin, oestradiol and FSH were monitored over the experiment. The levels of Aromatase P(450) and of the phosphorylated and non-phosphorylated forms of Akt, AMPK and ERK in granulosa cells and the concentration of oestradiol in follicular fluid, were determined. RESULTS: Glucose increased the circulating concentration of glucose (P < 0.05) and insulin (P < 0.05). It also increased the total number of follicles >1.0 mm in diameter (P < 0.05) and small (P < 0.05) follicles (>1.0 to 2.0 mm in diameter) but not medium (>2.0 to 3.5 mm in diameter) or large (>3.5 mm in diameter) follicles. Glucose decreased circulating oestradiol (P < 0.05) but not that of FSH or progesterone. Glucose reduced aromatase P(450) (P < 0.05) and decreased the phosphorylation of Akt (P < 0.05), ERK (P < 0.05) and AMPK (P < 0.05) in granulosa cells from oestrogenic follicles. The level of Aromatase P(450) was greatest in large oestrogenic follicles and the phosphorylation of Akt (P < 0.05), ERK (P < 0.05) and AMPK (P < 0.05) was lower in small follicles compared to medium and large follicles. CONCLUSIONS: These data suggest that the effect of glucose in small follicles is a direct action of glucose that increases the number of small follicles while the effect of glucose in oestrogenic follicles is an indirect insulin-mediated action. BioMed Central 2015-01-20 /pmc/articles/PMC4417278/ /pubmed/25604903 http://dx.doi.org/10.1186/1477-7827-13-6 Text en © Scaramuzzi et al.; licensee BioMed Central. 2015 This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Scaramuzzi, Rex John Zouaïdi, Nesrine Menassol, Jean-Baptiste Dupont, Joëlle The effects of intravenous, glucose versus saline on ovarian follicles and their levels of some mediators of insulin signalling |
title | The effects of intravenous, glucose versus saline on ovarian follicles and their levels of some mediators of insulin signalling |
title_full | The effects of intravenous, glucose versus saline on ovarian follicles and their levels of some mediators of insulin signalling |
title_fullStr | The effects of intravenous, glucose versus saline on ovarian follicles and their levels of some mediators of insulin signalling |
title_full_unstemmed | The effects of intravenous, glucose versus saline on ovarian follicles and their levels of some mediators of insulin signalling |
title_short | The effects of intravenous, glucose versus saline on ovarian follicles and their levels of some mediators of insulin signalling |
title_sort | effects of intravenous, glucose versus saline on ovarian follicles and their levels of some mediators of insulin signalling |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4417278/ https://www.ncbi.nlm.nih.gov/pubmed/25604903 http://dx.doi.org/10.1186/1477-7827-13-6 |
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