Disease relevance of IGFBP1

• These results demonstrate that EC IGFBP baseline expression as well as its expression in hypoxia vary in different vascular beds and suggest that the IGFBPs may be the dominant paracrine regulators of proliferation of EC as well as maintenance of endothelium integrity during hypoxia [1].
• Effect of an insulin-like growth factor binding protein fusion protein on thymidine incorporation in neuroblastoma and rhabdomyosarcoma cell lines [2].
• Concentrations of IGFBP-1 in uterine flushings did not change on either day [3].
• Thus, while selection for high versus low serum IGF-I concentrations has resulted in divergence between the selection lines and also in changes in body weights, it has not resulted in changes in serum IGFBP levels [4].
• A novel putative low-affinity insulin-like growth factor-binding protein, LIBC (lost in inflammatory breast cancer), and RhoC GTPase correlate with the inflammatory breast cancer phenotype [5].

High impact information on IGFBP1

• The determinants of insulin-like growth factor (IGF) binding to its binding proteins (IGFBPs) are poorly characterized in terms of important residues in the IGFBP molecule [6].
• Insulin-like growth factor (IGF)-I and IGF-II binding to an IGF binding protein. An investigation using chemical modification of tyrosine residues as a structural probe for the sites of interaction [7].
• The rat IGF binding protein is closely related to the partial amino acid sequences reported for a bovine IGF binding protein and more distantly related to a human IGF binding protein that recently has been cloned [8].
• A fusion protein, FP 6/3, composed of IGF binding protein (IGFBP)-6 and IGFBP-3 was synthesized where the complete sequences of each binding protein were fused together into a single chimeric protein [2].
• In conclusion, vascular endothelial growth factor and transforming growth factor-beta1 regulate IGFBP expression in bovine aortic endothelial cells [9].

Biological context of IGFBP1

• The relationship between ovarian follicular steroidogenesis and insulin-like growth factor binding protein (IGFBP) activity was evaluated during the follicular phase of the bovine estrous cycle [10].
• Allantoic fluid levels of IGFBP-1 were also increased in NT pregnancies [11].
• To examine IGFBP production by chondrocytes, we isolated bovine chondrocytes from adult articular, fetal articular, and fetal growth plate cartilage, and maintained them in primary culture as high-density monolayers or encapsulated in alginate beads [12].
• IGFBP-3 is the predominant mammary IGFBP and its concentration also declines in blood and milk during lactation compared to prepartum and involution periods [13].
• However, after 3 weeks, we observed a decreased IGFBP detection, and addition of 100 nmol/L IGF-I did not change IGFBP levels and did not modify cell growth [14].

Anatomical context of IGFBP1

• Perfused IGFBP1, 2, 3, and IGF-I also crossed the capillary boundary but in contrast to IGFBP4, preferentially localized in cardiac muscle with a connective tissue/muscle ratio of approximately 1:3 [15].
• As in the isolated heart, the IGFBP-1 preferentially localized to cardiac muscle with a connective tissue:cardiac muscle ratio of 1:3 [16].
• Profiles of IGFBP activity were similar in follicular fluid of small, medium, and E-I large follicles [10].
• Profiles of IGFBP activity in homogenates of granulosa or theca cells were similar to follicular fluid profiles except for the absence of IGFBP-3 binding activity [10].
• Tissue specificity and changes in abundance of IGFBPs in the uterus during early conceptus elongation indicate the potential importance of IGFBP regulation of uterine IGFs during this time period [17].

Associations of IGFBP1 with chemical compounds

• Intensities of the 34-kDa (IGFBP-2), 29-27-kDa, and 22-kDa IGFBP bands in follicular fluid were nondetectable or were lower (p < 0.01) in the fluid of large (> or = 8 mm) E-active (E-A; E2 > 50 ng/ml and > P4) follicles than in large E-inactive (E-I), medium (5-7 mm), or small (< 5 mm) follicles [10].
• These results suggest that the downstream effects of mechanical strain on IGF-I and IGFBP transcript levels are mediated, to greater or lesser extent, either through an angiotensin II tranducing pathway or via a feedback loop involving the autocrine secretion of IGF-I itself [18].
• The objectives of this study were to provide insight into the magnitude of variation in follicular fluid concentrations of steroids and activities of IGFBP that exists among individual small antral follicles within and between cows, and to determine the relationships between follicular fluid IGFBP and steroid concentrations in these follicles [19].
• Concentrations of E2 were correlated negatively with each IGFBP (r = -0.4 to -0.8; P < 0.05) except IGFBP-3 [19].
• In addition, the differential regulation of IGFBP-2, -3 and -6 by retinoic acid (which inhibits proliferation) and IGF-I (which stimulates proliferation) suggests that these forms of IGFBP have different roles in regulating mammary epithelial cell physiology [20].

Regulatory relationships of IGFBP1

• In contrast, the expression for IGFBP-1 was upregulated in the mammary gland of virgin heifers and increased around the onset of lactation. mRNA for GHR was found during all stages examined without outstanding fluctuations [21].

Other interactions of IGFBP1

• As IGFs are secreted in large amounts by the female reproductive tract, it has been hypothesized that maternal IGFs may affect embryonic growth and differentiation in a fine-tuned manner, involving modulation of IGF effects by embryonic IGFBP and IGF-I-R expression [22].
• IGFBP-4 was the predominant IGFBP expressed by both cell types and did not change with exposure to hypoxia [1].
• Pregnancy-associated plasma protein-A and insulin-like growth factor binding protein mRNAs in granulosa cells of dominant and subordinate follicles of preovulatory cattle [23].
• Individual total ligand (IGF-I + IGF-II) concentration and IGFBP pattern prepartum were largely regained 5 days post-partum in all cows [24].
• In this study we have investigated effects of delayed colostrum intake in neonatal calves on metabolic traits and on IGF-I, IGF binding proteins (IGFBP), growth hormone (GH), and insulin concentrations in plasma [25].

Analytical, diagnostic and therapeutic context of IGFBP1

• Follicular fluid was assayed for estradiol (E2), androstenedione (A4), progesterone (P4), and insulin-like growth factor-I (IGF-I) by RIA and for IGFBP activity by ligand blotting and densitometry [10].
• Effect of insulin-like growth factors (IGF), FSH, and leptin on IGF-binding-protein mRNA expression in bovine granulosa and theca cells: quantitative detection by real-time PCR [26].
• Total RNA was extracted from remnant liver and subjected to Northern blot hybridization with 32P-labelled cDNAs encoding rat IGFBP-1, -2 or -3 [27].
• The ovary bearing the DF was surgically removed by colpotomy, and individual follicles were utilized to study changes in concentrations of insulin like growth factor-I (IGF-I) and -II (IGF-II) and changes in amounts and proportions of the different IGF-binding proteins (IGFBP) present in follicular fluid (FF) [28].
• Media conditioned by MAC-T cells contained four forms of IGFBP that were identified, by western blotting with specific antibodies, as IGFBP-2, -3, -4 and -6 [20].

References