| insulin like growth factor 1 | OKDB#: 370 |
| Symbols: | IGF1 | Species: | human | ||
| Synonyms: | IGF, MGF, IGFI, IGF-I | Locus: | 12q23.2 in Homo sapiens |
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| General Comment | NCBI Summary: The protein encoded by this gene is similar to insulin in function and structure and is a member of a family of proteins involved in mediating growth and development. The encoded protein is processed from a precursor, bound by a specific receptor, and secreted. Defects in this gene are a cause of insulin-like growth factor I deficiency. Alternative splicing results in multiple transcript variants encoding different isoforms that may undergo similar processing to generate mature protein. [provided by RefSeq, Sep 2015] | ||||
| General function | Ligand, Hormone, Growth factor, Extracellular binding protein, Cell death/survival, Anti-apoptotic, DNA Replication, Cell proliferation, Metabolism | ||||
| Comment | Association of In Vitro Fertilization Outcome with Circulating Insulin-like Growth Factor Components Prior to Cycle Initiation. Ramer I et al. (2015) Components of the insulin-like growth factor (IGF) system enhance in vitro embryo quality and implantation rates in both animal models and in human IVF. We evaluated whether differences in serum levels of these components in women prior to initiation of an IVF cycle would be predictive of subsequent outcome. In this retrospective study sera from women obtained at day 2 of their IVF cycle (at baseline before stimulation) were assayed for IGF-I, IGF-II and IGF binding protein (BP)-1 by ELISA. Samples from 54 women with a live birth, 38 with a transient biochemical pregnancy, 45 with a spontaneous abortion, 54 who did not become pregnant and 35 who had an ectopic pregnancy were available for analysis. Associations between the assays and outcome were evaluated by the Kruskall Wallis test and ROC analysis. There were no differences in the number of oocytes retrieved, oocyte quality, fertilization rates, or embryo grade between groups. Median concentrations of IGF-I were elevated in women with a live birth (29.1 ng/ml) as compared to women with a biochemical pregnancy (25.6 ng/ml), spontaneous abortion (21.2 ng/ml), who were not pregnant (18.7 pg/ml) or who had an ectopic pregnancy (4.2 pg/ml) (p <0.001). Conversely, median levels of IGF-II were reduced in women with a live birth (294.5 ng/ml) as opposed to 357.5, 393.6, 407.2 and 426.9ng/ml in women with a biochemical pregnancy, ectopic pregnancy, spontaneous abortion or not pregnant, respectively (p<0.001). Median IGFBP-1 concentrations were markedly elevated in women with a live birth (23.6 ng/ml) compared to 18.3, 14.1, 13.8 and 9.5 ng/ml in women with a biochemical pregnancy, spontaneous abortion, not pregnant or with an ectopic pregnancy (p<0.001). The combination of IGF-I and IGFBP-1 best predicted the occurrence of a live birth with an area under the curve of 0.892. Maternal serum levels of IGF-I, IGF-II and IGFBP-1 prior to initiation of an IVF cycle are correlated with the likelihood of a live birth. Alterations in maternal IGF system components may influence oocyte quality or the success of early post-fertilization events and embryo implantation.////////////////// Dose-response study of intrafollicular injection of insulin-like growth factor-I on follicular fluid factors and follicle dominance in mares. Ginther OJ,et aal . The effect of insulin-like growth factor-I (IGF-I) on the concentrations of follicular fluid factors during follicle deviation and the development of dominance was studied in mares in two experiments. Transvaginal ultrasound guidance was used for intrafollicular injection and subsequent sequential sampling of follicular fluid. Treatment involved a single injection of IGF-I into the second-largest follicle (F2) at the expected beginning of deviation (Hour 0) based on diameter (>/=20 mm) of the largest follicle (F1). Mares in IGF-I groups were given a dose of 500 microg (experiment 1) or 250, 25, or 2.5 microg (experiment 2). Ablation of F1 at Hour 24 was done in experiment 1, but not in experiment 2. The 500- and 250-microg doses stimulated growth, leading to ovulation of F2 in 10 of 10 and 4 of 5 mares in the two experiments, respectively, compared to 4 of 12 and 0 of 5 in saline-injected controls. These doses prevented (P < 0.05) the increase in IGF binding protein-2 and androstenedione that occurred in F2 of controls and increased (P < 0.05) the concentrations of activin-A, inhibin-A, and vascular endothelial growth factor (VEGF). The 500-microg dose stimulated higher (P < 0.05) concentrations of estradiol, but not until Hour 48, whereas the lower doses were ineffective. In experiment 2, free IGF-I concentrations in F2 at Hour 24 decreased progressively as the dose decreased so that concentrations for the 2.5-microg dose were higher (P < 0.05) than in F2 of controls and similar (not significantly different) to endogenous concentrations in F1. Correspondingly, concentrations of androstenedione in F2 at Hour 24 were lower (P < 0.05) and concentrations of activin-A, inhibin-A, and VEGF were higher (P < 0.05) after treatment of F2 with the 2.5-microg dose than in F2 of controls and were similar to concentrations in F1. Hence, a physiologic intrafollicular dose of IGF-I did not stimulate estradiol production but reduced the production of androstenedione and stimulated the production of activin-A, inhibin-A, and VEGF during follicle selection in mares. Oropeza A, et al reported the improvement of the Developmental Capacity of Oocytes from Prepubertal Cattle by Intraovarian Insulin-Like Growth Factor-I Application. The developmental potential of oocytes from prepubertal cattle is decreased compared to those from their adult counterparts. The aim of the present study was to improve the developmental capacity of oocytes from prepubertal cattle by either systemic application of rbST or intraovarian injection of IGF-I. Blastocyst yields and the mRNA expression pattern (relative abundance, RA) of three putative marker genes (i.e. glucose transporter-1, Glut-1; eukaryotic translation initiation factor-1A, eIF1A and upstream binding factor, UBF) were selected as criteria to determine the success of the treatments. At 6-7 months of age, thirty healthy Holstein calves were randomly assigned to three experimental groups. The first group served as control and received an intraovarian injection of 0.6 ml acetic acid. The second group received a single s.c. injection of 500 mg of somatotropin (rbST). The third group received an intraovarian injection of 6 micro g rhIGF-I. During the following two weeks, follicles were aspirated 4 times via transvaginal ultrasound-guided technology. All animals were i.m. injected with 60 mg FSH 48 h prior to each aspiration. The treatments were repeated with the same animals at 9-10, 11-12 and 14-15 months of age. For comparison, five adult cows were i.m. injected each with 100 mg FSH and underwent oocyte retrieval. The proportion of oocytes considered to be developmentally competent was higher in cows than in calves (65% vs. 58%, 50%, 52%) for the control, rbST and IGF-I groups, respectively. The rate of blastocysts was similar in IGF-I treated calves and cows (28% and 25%) and was higher (P | ||||
| Cellular localization | Extracellular Matrix, Secreted, SNP | ||||
| Comment | candidate123 | ||||
| Ovarian function | Follicle development, Initiation of primordial follicle growth, Preantral follicle growth, Antral follicle growth, Follicle atresia, Steroid metabolism, Early embryo development | ||||
| Comment | Insulin-like growth factor-1 (IGF-1) promotes primordial follicle growth and reduces DNA fragmentation through the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signalling pathway. Bezerra MÉS et al. (2018) We investigated the effects of insulin-like growth factor 1 (IGF-1) on the morphology and follicular activation of ovine preantral follicles cultured in situ and whether the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway is involved in IGF-1 action in the sheep ovary. Ovine ovarian fragments were fixed for histological and terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) analyses (fresh control) or cultured in supplemented alpha-minimum essential medium (α-MEM+; control) or α-MEM+ with IGF-1 (1, 10, 50, 100 or 200ngmL-1) for 7 days. Follicles were classified as normal or atretic, primordial or growing and the oocyte and follicle diameters were measured. DNA fragmentation was evaluated by TUNEL assay. Proliferating cell nuclear antigen (PCNA) immunohistochemistry was performed on the fresh control, α-MEM+ and 100ngmL-1 IGF-1 samples. Inhibition of PI3K activity was performed through pretreatment with the PI3K inhibitor LY294002 and phosphorylated AKT (pAKT) expression was analysed after culture in the absence or presence of LY294002. IGF-1 at 100ngmL-1 increased (P<0.05) follicular activation compared with α-MEM+ and decreased TUNEL-positive cells (P<0.05) compared with other treatments. PCNA-positive cells also increased (P<0.05) in 100ngmL-1 IGF-1. LY294002 significantly inhibited follicular activation stimulated by α-MEM+ and 100ngmL-1 IGF-1 and reduced pAKT expression in follicles. Overall, IGF-1 at 100ngmL-1 promoted primordial follicle activation, cell proliferation and reduced DNA fragmentation after in situ culture through the PI3K/AKT pathway.////////////////// Stimulation of the largest subordinate follicle by intrafollicular treatment with insulin-like growth factor 1 is associated with inhibition of the dominant follicle in heifers. Shahiduzzaman AK et al. The effect of intrafollicular treatment of the second-largest follicle (F2) with insulin-like growth factor (IGF) 1 on the largest follicle (F1) and F2 was studied in heifers. Treatment of F2 was done when F1 reached >/=8.2 mm (expected beginning of follicle deviation; Day 0 or Hour 0). In each of two experiments, three groups (n = 6 or 7 heifers/group) were used: controls, F2 treated with vehicle and F2 treated with IGF1. The IGF1 treatment consisted of 200 mug of recombinant human IGF1 (pharmacological dose) in 20 muL of vehicle. In Experiment 1, the hypothesis that treatment of F2 with IGF1 has a stimulatory effect on F2 was supported by a greater (P < 0.05) incidence of F2 dominance (>/=10 mm) in the IGF1 group (71%) than in the other two groups (8%), and a greater (P < 0.02) growth rate of F2 on Days 0-2. Unexpectedly, treatment of F2 with IGF1 had an inhibitory effect on F1, as indicated by a reduced (P < 0.03) growth rate of F1 during Days 0-1 and Days 0-4 and a lesser (P < 0.05) maximum diameter of F1 in the IGF1 group. In Experiment 2, the hypothesis of an inhibitory effect on F1 when F2 was treated with IGF1 was supported by a lesser (P < 0.04) increase in diameter of F1 and a lesser (P < 0.04) percentage of follicle wall with power-Doppler signals of blood flow between Hours 0 and 14 in the IGF1 group. Circulating concentrations of FSH and LH were not altered significantly in either experiment. In conclusion, treatment of F2 with IGF1 at the expected beginning of deviation had a stimulatory effect on F2, but an inhibitory effect on F1. Adashi EY reviewed the literature on IGF system in the ovary. The large body of information now supports the existence of an intraovarian IGF system replete with ligands, receptors, and binding proteins. The intraovarian IGF system is most likely concerned with the amplification of gonadotropin hormonal action, other potential regulatory roles remaining speculative at this time. There is every reason to believe that work in this area in the upcoming several years will yield new insight necessary to establish whether or not IGFs are truly indispensable to ovarian function.Spicer LJ, et al 2000 studied effects of intraovarian infusion of insulin-like growth factor-I on ovarian follicular function in cattle. Fourteen cycling Holstein cows were divided equally into two groups: Control, osmotic minipumps (containing vehicle) surgically inserted into each ovary, or IGF-I treated, osmotic minipumps as in Controls but pumping 2.0 mu g of recombinant human IGF-I per hr for 7 days. Intraovarian IGF-I infusion increased concentrations of IGF-I in follicular fluid of small but not large follicles on Day 7 of treatment. Total ovarian weight (26.4 +/- 2.6 g), and size of the second largest (9.1 +/- 0.2 mm) follicle did not differ (P > 0.10) between control and IGF-I-treated cows. Size of the largest follicle was increased (P < 0.10) in IGF-I-treated versus control cows. IGF-I treatment increased (P < 0.05) estradiol concentrations in follicular fluid of small follicles, but had no effect (P < 0.10) on estradiol concentrations in follicular fluid of large follicles, or on progesterone, androstenedione, or IGF binding protein concentrations in small or large follicles. It was concluded that a 7-day infusion of IGF-I directly into the stroma of the ovary altered follicular growth and follicular fluid estradiol concentrations. Expression of IGFs and their receptors is a potential marker for embryo quality. Liu HC et al. PROBLEM: Insulin-like growth factors (IGFs) and insulin have been demonstrated to stimulate oocyte maturation and embryo development. Therefore, the expression of IGFs and their receptors may be an important intrinsic factor for embryo growth and may be a potential marker for embryo quality. METHOD OF STUDY: Thirty donated day 3 embryos were cultured in vitro for an additional 3 days to observe their developmental potential and were semiquantitatively analyzed for the expression of IGF-I, IGF-II, IGF-IR, IGF-IIR, and insulin-R. RESULTS: Our results show that the activity of these gene expressions correlates well with the morphological assessment and that high and more gene expressions were often associated with embryos of high growth potential. CONCLUSION: The IGF system may indeed play an important role in human embryogenesis; IGF gene expressions can be a good indicator of embryonic developmental stage and/or growth potential; finally, the IGF system can serve as a marker for embryo quality. Effect of IGF-I on pig oocyte maturation, fertilization, and early embryonic development in vitro, and on granulosa and cumulus cell biosynthetic activity. Xia P et al. Porcine granulosa cells have been shown previously to both secrete and respond to insulin-like growth factor-I (IGF-I), suggesting an autocrine function of this peptide in the follicle. The present work was undertaken to determine possible effects of IGF-I on in vitro maturation, in vitro fertilization, and early embryonic development in culture. Granulosa and cumulus cell proliferation and differentiation based on 3H-thymidine uptake and progesterone production, respectively, were also assessed. The results showed that the cleavage rate of oocytes was markedly stimulated in a dose-dependent manner by the addition of IGF-I to the oocyte maturation medium (P < 0.05). Embryo development beyond the 8-cell stage was improved by IGF-I, reaching a maximum of 22% at 200 ng/ml IGF-I. Treatment with IGF-I after fertilization increased the percentage of total oocyte cleavage (P < 0.05) to approximately 52%, 43%, and 57% at, respectively, 25, 50, and 100 ng/ml IGF-I. 3H-thymidine incorporation by granulosa cells was significantly increased in cultures treated with FSH (3-fold) or IGF-I (6-fold) compared to the control. For the cumulus cells, FSH caused a similar increase (3-fold) in 3H-thymidine incorporation while IGF-I stimulated a 15-fold increase. Progesterone production by the granulosa cells was increased to the same extent by treatment with FSH or IGF-I (4.7 and 5.1-fold, respectively). However, for the cumulus cells, while FSH caused a marked 16-fold increase in progesterone production, IGF-I caused only a marginal increase of 2.5-fold.(ABSTRACT TRUNCATED AT 250 WORDS) | ||||
| Expression regulated by | FSH, LH, Steroids, Growth Factors/ cytokines | ||||
| Comment | |||||
| Ovarian localization | Granulosa, Theca, Luteal cells | ||||
| Comment | |||||
| Follicle stages | Secondary, Antral, Preovulatory, Corpus luteum | ||||
| Comment | |||||
| Phenotypes |
PCO (polycystic ovarian syndrome) |
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| Mutations |
5 mutations
Species: mouse
Species: human
Species: human
Species: ovine
Species: human
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| Genomic Region | show genomic region | ||||
| Phenotypes and GWAS | show phenotypes and GWAS | ||||
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| created: | Jan. 8, 2000, midnight | by: |
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| last update: | March 22, 2020, 10:02 a.m. | by: | hsueh email: |
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