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Kikuchi K, Sasaki K, Akizawa H, Tsukahara H, Bai H, Takahashi M, Nambo Y, Hata H, Kawahara M. Identification and expression analysis of cDNA encoding insulin-like growth factor 2 in horses. J Reprod Dev 2018; 64:57-64. [PMID: 29151450 PMCID: PMC5830359 DOI: 10.1262/jrd.2017-124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Insulin-like growth factor 2 (IGF2) is responsible for a broad range of physiological processes during fetal development and adulthood, but genomic analyses of IGF2 containing the 5ʹ- and
3ʹ-untranslated regions (UTRs) in equines have been limited. In this study, we characterized the IGF2 mRNA containing the UTRs, and determined its expression pattern in the fetal tissues of horses. The
complete equine IGF2 mRNA sequence harboring another exon approximately 2.8 kb upstream from the canonical transcription start site was identified as a new transcript variant. As this upstream exon did
not contain the start codon, the amino acid sequence was identical to the canonical variant. Analysis of the deduced amino acid sequence revealed that the protein possessed two major domains, IlGF and IGF2_C, and
analysis of IGF2 sequence polymorphism in fetal tissues of Hokkaido native horse and Thoroughbreds revealed a single nucleotide polymorphism (T to C transition) at position 398 in Thoroughbreds, which
caused an amino acid substitution at position 133 in the IGF2 sequence. Furthermore, the expression pattern of the IGF2 mRNA in the fetal tissues of horses was determined for the first time, and was
found to be consistent with those of other species. Taken together, these results suggested that the transcriptional and translational products of the IGF2 gene have conserved functions in the fetal
development of mammals, including horses.
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Affiliation(s)
- Kohta Kikuchi
- Laboratory of Animal Genetics and Reproduction, Research Faculty of Agriculture, Hokkaido University, Hokkaido 060-8589, Japan
| | - Keisuke Sasaki
- Laboratory of Animal Genetics and Reproduction, Research Faculty of Agriculture, Hokkaido University, Hokkaido 060-8589, Japan.,Present: Department of Bioscience, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Hiroki Akizawa
- Laboratory of Animal Genetics and Reproduction, Research Faculty of Agriculture, Hokkaido University, Hokkaido 060-8589, Japan
| | - Hayato Tsukahara
- Laboratory of Animal Genetics and Reproduction, Research Faculty of Agriculture, Hokkaido University, Hokkaido 060-8589, Japan
| | - Hanako Bai
- Laboratory of Animal Genetics and Reproduction, Research Faculty of Agriculture, Hokkaido University, Hokkaido 060-8589, Japan
| | - Masashi Takahashi
- Laboratory of Animal Genetics and Reproduction, Research Faculty of Agriculture, Hokkaido University, Hokkaido 060-8589, Japan
| | - Yasuo Nambo
- Equine Science Division, Hidaka Training and Research Center, Japan Racing Association, Hokkaido 057-0171, Japan.,Present: Department of Clinical Veterinary Sciences, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan
| | - Hiroshi Hata
- Field Science Center for Northern Biosphere, Hokkaido University, Hokkaido 060-0811, Japan
| | - Manabu Kawahara
- Laboratory of Animal Genetics and Reproduction, Research Faculty of Agriculture, Hokkaido University, Hokkaido 060-8589, Japan
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Melo AN, Santos Júnior ER, Silva DF, Adrião M, Porto AL, Wischral A. Expressão do mRNA para IGF-2 em oócitos e células do cumulus extraídos de folículos antrais e pré-antrais de ovelhas nativas do Estado de Pernambuco. PESQUISA VETERINARIA BRASILEIRA 2017. [DOI: 10.1590/s0100-736x2017000500017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
RESUMO: Objetivou-se avaliar a expressão do mRNA para o gene do fator de crescimento IGF-2 em oócitos e células do cumulus de ovelhas em diferentes estágios do desenvolvimento folicular. Os folículos classificados morfologicamente como antrais (terciários e pré-ovulatórios) foram aspirados manualmente para obtenção dos oócitos e células do cumulus. Os folículos pré-antrais (secundários) foram extraídos do córtex ovariano, por microdissecção, e os oócitos retirados. Nos dois grupos, os oócitos foram desnudados e agrupados em “pools” de dez células cada (Grupo A, n=10; Grupo B, n=10) e dez amostras com grupos de células do cumulus (Grupo A1, n=10, B1, n=10). O mRNA foi extraído e convertido em cDNA utilizando a técnica da RT-PCR, utilizando Oligo DT randômico para o mRNA. A análise da expressão confirmou a expressão gênica para IGF-2 nos grupos de oócitos e células do cumulus. Houve um aumento da expressão relativa do mRNA para IGF-2 nos grupos de oócitos durante a fase mais tardia do desenvolvimento folicular e as diferenças foram consideradas significantes (p<0,05). Não houve variação significante da expressão de IGF2 entre os grupos de células do cumulus. Conclui-se que o fator de crescimento IGF-2 tem níveis mais elevados de expressão em oócitos ovinos, na segunda fase do desenvolvimento folicular, mas expressão semelhante em células do cumulus durante as fases estudadas do desenvolvimento folicular.
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Salazar-Ortiz J, Monget P, Guillaume D. The influence of nutrition on the insulin-like growth factor system and the concentrations of growth hormone, glucose, insulin, gonadotropins and progesterone in ovarian follicular fluid and plasma from adult female horses (Equus caballus). Reprod Biol Endocrinol 2014; 12:72. [PMID: 25078409 PMCID: PMC4237953 DOI: 10.1186/1477-7827-12-72] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 07/22/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Feed intake affects the GH-IGF system and may be a key factor in determining the ovarian follicular growth rate. In fat mares, the plasma IGF-1 concentration is high with low GH and a quick follicular growth rate, in contrast to values observed in thin mares. Nothing is known regarding the long-term effects of differential feed intake on the IGF system. The objective of this experiment was to quantify IGFs, IGFBPs, GH, glucose, insulin, gonadotropin and progesterone (P4) in blood and in preovulatory follicular fluid (FF) in relation to feeding levels in mares. METHODS Three years prior to the experiment, Welsh Pony mares were assigned to a restricted diet group (R, n = 10) or a well-fed group (WF, n = 9). All mares were in good health and exhibited differences in body weight and subcutaneous fat thickness. Follicular development was scanned daily and plasma was also collected daily. Preovulatory FF was collected by ultrasound-guided follicular aspiration. Hormone levels were assayed in FF and plasma with a validated RIA. RESULTS According to scans, the total number of follicles in group R was 53% lower than group WF. Insulin and IGF-1 concentrations were higher in WF than in R mares. GH and IGF-2 concentrations were lower in plasma from WF mares than from R mares, but the difference was not significant in FF. The IGFBP-2/IGFBP-3 ratio in FF was not affected by feeding but was dramatically increased in R mare plasma. No difference in gonadotropin concentration was found with the exception of FSH, which was higher in the plasma of R mares. On the day of puncture, P4 concentrations were not affected by feeding but were higher in preovulatory FF than in plasma. CONCLUSIONS The bioavailability of IGF-1 or IGF-2, represented by the IGFBP2/IGFBP3 ratio, is modified by feed intake in plasma but not in FF. These differences partially explain the variability in follicular growth observed between well-fed mares and mares on restricted diets.
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Affiliation(s)
- Juan Salazar-Ortiz
- INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France
- CNRS, UMR6175 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France
- Université François Rabelais de Tours, F-37041 Tours, France
- IFCE, F-37380 Nouzilly, France
| | - Philippe Monget
- INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France
- CNRS, UMR6175 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France
- Université François Rabelais de Tours, F-37041 Tours, France
- IFCE, F-37380 Nouzilly, France
| | - Daniel Guillaume
- INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France
- CNRS, UMR6175 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France
- Université François Rabelais de Tours, F-37041 Tours, France
- IFCE, F-37380 Nouzilly, France
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Influence of mineral supplementation on oxidative stress, ovarian follicles growth and reproductive hormone concentration in cyclic Arab mares. ASIAN PACIFIC JOURNAL OF REPRODUCTION 2013. [DOI: 10.1016/s2305-0500(13)60107-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Cuervo-Arango J, Clark A. The first ovulation of the breeding season in the mare: The effect of progesterone priming on pregnancy rate and breeding management (hCG response rate and number of services per cycle and mare). Anim Reprod Sci 2010; 118:265-9. [DOI: 10.1016/j.anireprosci.2009.08.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 08/03/2009] [Accepted: 08/17/2009] [Indexed: 11/17/2022]
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Abstract
The mare provides a unique experimental model for studying follicle development in monovular species. Development of antral follicles in horses is characterized by the periodic growth of follicular waves which often involve the selection of a single dominant follicle. If properly stimulated, the dominant follicle will complete development and eventually ovulate a fertile oocyte. Regulation of follicular wave emergence and follicle selection involves an interplay between circulating gonadotropins and follicular factors that ensures that individual follicles are properly stimulated to grow (or to regress) at any given stage of follicular wave development. Periodic development of follicular waves continuously occurs during most of post-natal life in the mare and is influenced by factors such as stage of oestrous cycle, season, pregnancy, age, breed and individual so that different types of follicular waves (minor or major, ovulatory or anovulatory) and different levels of activity within waves may develop under different physiological conditions. Changes in gonadotropin levels and/or in the sensitivity of follicles to circulating gonadotropins seem to account largely for these physiological variations in follicle development.
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Affiliation(s)
- F X Donadeu
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK.
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Doyle LK, Hogg CO, Watson ED, Donadeu FX. Seasonal effects on the response of ovarian follicles to IGF1 in mares. Reproduction 2008; 136:589-98. [DOI: 10.1530/rep-07-0507] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The response of follicles to IGF1 was compared between the transition into the ovulatory season (transitional period) and the ovulatory season (ovulatory period) in eight mares using a cross-over experimental design within periods. Granulosa cells were collected from follicles 15–24 or 25–34 mm and expression ofIGF1R,IGF2R,FSHR,LHCGRandPAPPAwas determined by qPCR. In addition, 10 mg IGF1 or vehicle were injected into the largest follicle (transitional period) or the second largest follicle (ovulatory period) of a follicular wave before the beginning of diameter deviation between the two largest follicles (mean diameters at injection 19.2 and 20.0 mm during transitional and ovulatory periods respectively). Follicular fluid was collected 24 h after injection for determination of free IGF1, IGFBP, inhibin A and oestradiol levels. Granulosa cells from follicles 25–34 mm, but not follicles 15–24 mm, expressed higher levels ofIGF1R(P=0.01),FSHR(P<0.007) andLHCGR(P=0.09) during the ovulatory period than during the transitional period, whereasIGF2Rexpression was higher in transitional than ovulatory follicles (P=0.06). Follicular IGFBP2 levels were not different (P>0.1) between periods and treatments, whereas IGFBP5 levels were higher (P<0.05) during the ovulatory period. Finally, IGF1 injection before the beginning of deviation induced an approximately twofold increase (P=0.01) in follicular inhibin A levels during each period and did not affect oestradiol (P>0.1). These results suggest that, as during ovulatory waves, equine follicles during transitional waves are responsive to IGF1 before the beginning of deviation and that, therefore, inadequate IGF1 responsiveness before deviation may not underlie the deficient development of dominant follicles during transition.
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Donadeu FX, Watson ED. Seasonal changes in ovarian activity: Lessons learnt from the horse. Anim Reprod Sci 2007; 100:225-42. [PMID: 17207590 DOI: 10.1016/j.anireprosci.2006.12.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 11/24/2006] [Accepted: 12/04/2006] [Indexed: 11/16/2022]
Abstract
The annual reproductive cycle in the horse involves a reduction in ovarian activity during short days. The absence of ovulatory activity during winter has important consequences for an equine industry eager to breed mares early during the year. The anovulatory season results from a reduction in the secretion of pituitary gonadotropin that is in turn triggered by the inhibitory effects of short photoperiod on the hypothalamus-pituitary axis. Recent studies have provided evidence that the response of the ovaries to endocrine stimuli during the anovulatory season is affected not only by circulating concentrations of trophic hormones but also by locally produced growth factors that are putative modulators of follicular responses to gonadotropins. The present review summarises current knowledge on ovarian dynamics during the equine anovulatory season and the regulatory mechanisms involved at both systemic and local levels.
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Affiliation(s)
- F X Donadeu
- Easter Bush Veterinary Centre, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian EH25 9RG, UK.
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Spicer LJ, Santiago CA, Davidson TR, Bridges TS, Chamberlain CS. Follicular fluid concentrations of free insulin-like growth factor (IGF)-I during follicular development in mares. Domest Anim Endocrinol 2005; 29:573-81. [PMID: 16213990 DOI: 10.1016/j.domaniend.2005.03.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Revised: 02/24/2005] [Accepted: 03/16/2005] [Indexed: 12/25/2022]
Abstract
The objective of the present study was to evaluate changes in concentrations of free insulin-like growth factor (IGF)-I in follicular fluid (FFL) during follicle development in the mare. Mares (n = 14) were classified as either in the follicular phase (n = 8) or luteal phase (n = 6). Follicles (n = 92) were categorized as small (6-15 mm; n = 54), medium (16-25 mm; n = 23) or large (>25 mm; n = 15) and FFL was collected. Free IGF-I levels in FFL in large follicles of follicular phase mares were greater (P < 0.05) than in large follicles of luteal phase mares and small or medium follicles of luteal and follicular phase mares. Free IGF-I concentrations were greater (P < 0.05) in large follicles of luteal phase mares than small but not medium follicles of luteal phase mares. FFL ratio of estradiol:progesterone paralleled changes in free IGF-I. Free IGF-I concentrations were negatively correlated (P < 0.05) with insulin-like growth factor binding protein (IGFBP)-2, -4 and -5 but not IGFBP-3 levels. In addition, free IGF-I concentrations in FFL were positively correlated (P < 0.01) with FFL estradiol, progesterone, androstenedione, estradiol:progesterone ratio, total IGF-I and total IGF-II. We conclude that increases in intrafollicular levels of bioavailable (free) IGF-I are associated with increased steroidogenesis in developing mare follicles.
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Affiliation(s)
- L J Spicer
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA.
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Watson ED, Bae SE, Al-Zi'abi MO, Hogg CO, Armstrong DG. Expression of mRNA encoding insulin-like growth factor binding protein-2 (IGFBP-2) during induced and natural regression of equine corpora lutea. Theriogenology 2005; 64:1371-80. [PMID: 16139613 DOI: 10.1016/j.theriogenology.2005.02.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 02/21/2005] [Accepted: 02/23/2005] [Indexed: 10/25/2022]
Abstract
The insulin-like growth factors, IGF-I and -II, have been shown to play a key role in luteal function in some species. The IGF binding proteins, IGFBP-2 and -3, have been shown to inhibit binding of IGF-I and -II to bovine luteal cells and decrease progesterone production. We have recently shown that equine follicles have the genetic capacity to produce IGFBP-2, and that levels decrease in healthy preovulatory follicles. In the present study expression of mRNAs encoding IGFBP-2, as well as the rate-limiting steroidogenic enzyme, P450scc, were studied in equine corpora lutea to investigate whether IGFBP-2 might be involved in luteolysis. Corpora lutea were collected from mares in mid-luteal phase (day 10), at early regression (day 14), late regression (day 17), and 12 and 36 h after intramuscular administration of the PGF(2alpha) analogue, cloprostenol (0.5 microg/kg). During early natural regression, and 12 h after administration of cloprostenol on day 10, steady state levels of mRNAs encoding P450scc had decreased significantly compared with day 10 of dioestrus (P < 0.001). Levels of mRNA encoding IGFBP-2 increased significantly between mid-diestrus and early (P < 0.01) and late (P < 0.001) regression, and 36 h after cloprostenol administration (P < 0.001). We conclude that the genetic capacity for increased IGFBP-2 production in the early stages of natural luteolysis in the mare may act to sequester IGF-I in the CL, assisting in inhibition of progesterone production. However the delay in increase in mRNA encoding IGFBP-2 after cloprostenol administration, combined with the sharp fall in expression of P450scc mRNA, suggests that the luteolytic action of a pharmacological dose of cloprostenol may not be mediated via IGFBP-2 in the mare.
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Affiliation(s)
- E D Watson
- Royal (Dick) School of Veterinary Studies, Department of Veterinary Clinical Studies, Veterinary Field Station, University of Edinburgh, Easter Bush, Midlothian, Scotland EH25 9RG, UK.
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