Disease relevance of IGFBP2

• IGF binding protein (BP) activity was affected by diabetes mellitus, with untreated diabetic pigs having greater IGFBP-1 activity in medium and with both diabetic groups having greater IGFBP-2 activity in follicular fluid (p < 0.05) [1].
• IGFBP-2 mRNA increased (P<0.001) in liver of IUGR fetuses [2].
• Late in gestation, fetal weight, placental weight and total exchange surface area in the placenta were each negatively correlated with maternal plasma IGFBP-2 concentration (all P < 0.01), while the arithmetic mean thickness of syncytiotrophoblast was positively correlated with maternal plasma IGFBP-2 concentration [3].
• Multiple regression analysis showed that maternal weight gain was negatively associated with circulating IGF-II and IGFBP-2 [4].

High impact information on IGFBP2

• Porcine aortic smooth muscle cells secrete a serine protease for insulin-like growth factor binding protein-2 [5].
• Previously, we have reported that porcine VSMCs synthesize and secrete IGF-I and several forms of IGFBPs, including IGFBP-2, IGFBP-4, and IGFBP-5 [6].
• Previous studies have shown that porcine aortic smooth muscle cells (SMCs) secrete two insulin-like growth factor-binding proteins (IGFBP), IGFBP-2 and -4, and that these IGFBPs modulate IGF-I-stimulated SMC proliferation and migration [7].
• IGFBP-2 mRNA persisted in granulosa cells of preovulatory follicles and corpora lutea [8].
• In summary, there is selective expression of IGF-I, IGF-I receptor, and IGFBP-2 and -4 mRNAs during the process of follicular selection in the gilt ovary, with IGFBP-4 expression being closely associated with follicular selection and luteinization [8].

Biological context of IGFBP2

• The present study examined whether IGF-II and a major uterine-expressed IGF-II binding protein, IGFBP-2, modulate endometrial epithelial cell mitogenesis [9].
• At equimolar concentrations, Des(1-6)IGF-II (an IGF-II analog with much reduced affinity for IGFBPs) and rpIGFBP-2 had additive effects on GE cell mitogenesis, suggesting that the IGFBP-2 modulation of uterine cell growth may involve both IGF-dependent and IGF-independent pathways [9].
• Hepatic IGFBP-2 mRNA and serum IGFBP-2 levels increased during the latter half of gestation and then declined postnatally [10].
• Gene expression for IGFBP-d decreased (P < 0.04) from day 3 to day 5, while expression of IGFBP-2 was unaffected by treatment or day [11].
• In summary, increased fetal growth in somatotropin-treated pregnant pigs was not associated with changes in IGF or IGFBP-2 mRNA concentration in reproductive tissues [12].

Anatomical context of IGFBP2

• In contrast, IGFBP-2 mRNA levels were higher in endometrium than in placenta and myometrium [13].
• IGFBP-2 mRNA was most abundant in granulosa cells of small follicles and in the ovarian vasculature regardless of cycle stage [8].
• In pregnant pig endometrium and rat uterus, levels of IGF-I mRNA decreased, while those of IGF-II and IGFBP-2 mRNAs increased with stage of pregnancy [13].
• In conclusion, the expression of IGF-I and IGFBP-2 mRNAs in the ovarian follicle are discordantly regulated during follicular growth and maturation [14].
• Endometrial expression of IGF-II mRNAs was limited to surface and glandular epithelial cells; epithelial and stromal cells expressed IGFBP-2 mRNAs at comparable levels [13].

Associations of IGFBP2 with chemical compounds

• IGFBP-2 mRNA was correlated with both day and diameter (r = -.713 and -.705, respectively, n = 24) and neither estrogen (E2) nor progesterone (P4) contributed to the fit [14].
• Regression analysis of IGF-I and IGFBP-2 mRNA expression was performed to assess the relative strength of correlations with day, diameter and steroid concentrations as covariates [14].
• In experiment 3, progesterone remained elevated from 0 to 36 h after hCG, even though IGFBP-2 did not increase until after 24 h post-hCG.(ABSTRACT TRUNCATED AT 250 WORDS)[15]
• In experiments 1 and 2, IGFBP-3 in follicular fluid remained constant over follicle diameters and stage sof development, and IGFBP-2 decreased with advancing follicular development as concentrations of estradiol, androstenedione, and progesterone increased [15].
• We therefore examined the associations between placental structural parameters, the ratios of maternal to fetal plasma glucose and fetal to maternal plasma urea concentration, and maternal circulating IGF-I, IGF-II and IGFBP-2 in ad libitum fed and food restricted (70-90 per cent of the ad libitum intake) pregnant guinea pigs [3].

Physical interactions of IGFBP2

• Porcine granulosa cells (GC) produce insulin-like growth factor (IGF) binding protein (BP)-3 and IGFBP-2 in culture [16].

Regulatory relationships of IGFBP2

• GH for either 20 days or 40 days increased serum IGBP-3 to 140% and 250% of control values while decreasing serum IGFBP-2 by 46% and 31%, respectively (p < 0.001) [17].

Other interactions of IGFBP2

• IUGR was associated with elevated plasma IGFBP-2 and IGFBP-4 and reduced IGFBP-3 levels [2].
• Ligand blot analysis of granulosa cell (GC)-conditioned culture medium revealed several easily measurable insulin-like growth factor (IGF)-binding proteins (IGFBPs), including IGFBP-3 [40-44 kilodaltons (kDa)] and IGFBP-2 (34 kDa) [18].
• The mRNA for IGF-I, IGF-II, IGFBP-2, LH receptor, FSH receptor, cytochrome P450 side-chain cleavage (P450scc), 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), 17 alpha-hydroxylase (P45017 alpha), and aromatase (P450arom) were detected by in situ hybridization, and relative amounts were determined by image analysis [19].
• IGF-I, IGFBP-2 and -3 but not GH concentrations are different in normal and poor growing piglets [20].
• Serum GH, IGF-I, IGF-II and IGFBP-2 concentrations were determined by radioimmunoassay in swine of genetic lines which were selected for high (obese) and low (lean) backfat [21].

Analytical, diagnostic and therapeutic context of IGFBP2

• The uterine IGFBP doublet was identified as IGFBP-2 by immunoprecipitation [22].
• Hypophysectomy decreased serum levels of IGF binding protein 1 (IGFBP-1) (90 days) and IGFBP-2 (105 days) and increased IGFBP-4 (105 days) in comparison with control [23].
• The mRNAs for somatotropin receptor, IGFs -I and -II, IGFBP-2 and pregnancy-associated glycoprotein (a marker of trophoblast tissue) were analyzed by Northern blotting or ribonuclease protection assay [12].
• Concentrations of IGFBP-2 and -3 were determined by ligand blot analysis with 125I-labelled insulin-like growth factor II and quantified by densitometry [24].
• Plasma IGF-I concentration was measured by radioimmunoassay and plasma IGFBP-3 and IGFBP-2 were estimated by Western ligand blotting [25].

References