Insulin-like growth factor 1 (IGF-1) gene expression in porcine ovarian tissue

Charlton, S.; Cameron, B. J.; Glimm, David R.; Foxcroft, G. R.; Kennelly, J. J.

doi:10.4141/cjas93-027

Cited by 7 publications

(5 citation statements)

References 14 publications

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“…Ribonuclease protection assay IGF-I mRNA in all samples was measured in an RNase protection assay procedure as described by Gilman (1987) but with modifications as follows. As a human IGF-I riboprobe has already been used in our laboratory to establish the expression of the IGF-I gene in the pig ovary by Northern blot analysis (Charlton et al 1993), we used an available human exon 3 IGF-I riboprobe to develop a heterologous human-pig RNase protection assay. Duplicate ali¬ quots of 50 pg sample total RNA were hybridized overnight with 5 x 106 d.p.m.…”

Section: Animalsmentioning

confidence: 99%

“…In order to reduce RNA degradation within ovarian tissue, follicles were removed in as short a time as possible (approximately 2 min per ovary) by coarse dissection of individual follicles from the frozen ovary and immediate sub¬ mersion of the follicular tissue in liquid nitrogen. Total RNA was isolated from each ovarian sample, and from a 0-5 g sample of liver from the same animal, using the guanidine isothiocyanate/caesium chloride procedure described by Chirgwin et al (1979) with modifications as described by Charlton et al (1993). The quantity and purity of the RNA obtained was determined by ultraviolet spectrophotometry at 260 and 280 nm.…”

Section: Animalsmentioning

confidence: 99%

“…The insulin-like growth factor í (ÍGF-I) gene is expressed in the porcine ovary (Cameron et al 1990;Charlton et al 1993) as well as in cardiac and skeletal muscle (Leaman et al 1990), the uterus (Tavakkol et al 1988), liver and adipose tissue (Simmen et al 1992). In vitro, IGF-I affects both granulosa cell differentiation and function: it potentiates many of the actions of follicle-stimulating hormone (FSH) (Adashi et al 1985;Davoren et al 1985) and affects granulosa cell metabolism (Veldhuis et al 1987;Weber & LaBarbera, 1988).…”

Section: Introductionmentioning

confidence: 99%

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Ovarian and hepatic insulin-like growth factor-I gene expression and associated metabolic responses in prepubertal gilts subjected to feed restriction and refeeding

Charlton

Cosgrove²,

Glimm³

et al. 1993

Journal of Endocrinology

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The effects of feed restriction and refeeding on ovarian and hepatic insulin-like growth factor-I (IGF-I) gene expression, systemic and ovarian IGF-I concentrations and on associated metabolic changes were measured in prepubertal gilts. Eleven pairs of littermate gilts (70.7 +/- 4.7 kg) were placed on a maintenance level of feeding for 7 days (days 1-7). On day 8, littermates were either fed at a maintenance level of energy or fed to appetite for a further 6 days. Blood samples were taken on day 13 (07.00-16.00 h) to determine plasma insulin and IGF-I, and on day 14 (02.00-06.00 h) to determine plasma GH levels. Following slaughter on day 14, one ovary from each animal was retained to measure follicular fluid IGF-I and oestradiol concentrations. The remaining ovary and a sample of liver were retained for IGF-I mRNA analysis using a ribonuclease protection assay. Six days of refeeding significantly increased plasma IGF-I (P < 0.005) and basal insulin (P < 0.05) but there was no effect on plasma GH. Ovarian follicular volume and diameter were significantly larger after refeeding (P < 0.05), with no effect on follicular fluid oestradiol concentrations. Mean follicular fluid IGF-I concentrations were unaffected by treatment. However, the relationships between individual follicular IGF-I concentrations, absolute follicular fluid IGF-I contents and follicle volume were affected by feeding level (P < 0.05). Regression analysis of the same data also revealed that at this stage of maturity, small follicles had greater follicular fluid concentrations of IGF-I than larger follicles. Refeeding increased the amount of IGF-I mRNA in hepatic but not ovarian tissue. We conclude that there is differential regulation of the IGF-I gene in porcine hepatic and ovarian tissues, and that ovarian factors other than, or as well as, IGF-I are involved in the regulation of ovarian responses to refeeding.

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Section: Animalsmentioning

confidence: 99%

Section: Animalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ovarian and hepatic insulin-like growth factor-I gene expression and associated metabolic responses in prepubertal gilts subjected to feed restriction and refeeding

Charlton

Cosgrove²,

Glimm³

et al. 1993

Journal of Endocrinology

Self Cite

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“…In particular, IGF-1 exerts multiple physiologic effects on the systemic vasculature through endocrine, autocrine or paracrine mechanisms [2]. Many studies have reported that IGF-1 widely exists in mammalian ovarian tissues and is indispensable to follicle growth [3,4,5]. For example, the development of ovaries from the mouse deleted IGF-1 gene was incomplete, with the follicles arresting at the pre-antral or early antral stage and the mitotic abilities of granulosa cells presenting as weak [6].…”

Section: Introductionmentioning

confidence: 99%

IGF-1 Inhibits Apoptosis of Porcine Primary Granulosa Cell by Targeting Degradation of BimEL

Han¹,

Wang²,

Wang³

et al. 2019

IJMS

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Insulin-like growth factor-1 (IGF-1) is an intra-ovarian growth factor that plays important endocrine or paracrine roles during ovarian development. IGF-1 affects ovarian function and female fertility through reducing apoptosis of granulosa cells, yet the underlying mechanism remains poorly characterized. Here, we aimed to address these knowledge gaps using porcine primary granulosa cells and examining the anti-apoptotic mechanisms of IGF-1. IGF-1 prevented the granulosa cell from apoptosis, as shown by TUNEL and Annexin V/PI detection, and gained the anti-apoptotic index, the ratio of Bcl-2/Bax. This process was partly mediated by reducing the pro-apoptotic BimEL (Bcl-2 Interacting Mediator of Cell Death-Extra Long) protein level. Western blotting showed that IGF-1 promoted BimEL phosphorylation through activating p-ERK1/2, and that the proteasome system was responsible for degradation of phosphorylated BimEL. Meanwhile, IGF-1 enhanced the Beclin1 level and the rate of LC3 II/LC3 I, indicating that autophagy was induced by IGF-1. By blocking the proteolysis processes of both proteasome and autophagy flux with MG132 and chloroquine, respectively, the BimEL did not reduce and the phosphorylated BimEL protein accumulated, thereby indicating that both proteasome and autophagy pathways were involved in the degradation of BimEL stimulated by IGF-1. In conclusion, IGF-1 inhibited porcine primary granulosa cell apoptosis via degradation of pro-apoptotic BimEL. This study is critical for us to further understand the mechanisms of follicular survival and atresia regulated by IGF-1. Moreover, it provides a direction for the treatment of infertility caused by ovarian dysplasia, such as polycystic ovary syndrome and the improvement of assisted reproductive technology.

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“…Interestingly, follicular IGF-1 levels were elevated above peripheral levels and there was no correlation between the two, implying de novo synthesis of IGF-1 in the follicle. Indeed, the ovarian follicle of the prepubertal gilt does synthesize IGF-1 (Charlton et al 1993a) and there appears to be differential regulation of hepatic (and, consequently, peripheral) and ovarian (local) IGF-1 synthesis ( Fig. 3b; Charlton et al 1993b).…”

Section: Nutritional Modulation Of Ovarian Functionmentioning

confidence: 99%