Disease relevance of IGFBP1

• 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].
• Concentrations of IGF-BP did not change in porcine serum following acute challenges with pGH (10-1000 micrograms/kg body weight) or IGF-I (4 or 8 mg per pig) [2].
• Finally, IGFBP-1 and -2 may have different roles during chronic undernutrition compared with unrestrained nutrition in adult life [3].
• IGFBP-1 and -2 were negatively correlated to weight gain and food conversion efficiency in the ad libitum-fed group, while IGF-I, -II, IGFBP-1, -3 and -4 were positively correlated to body weight, weight gain and food conversion efficiency in the food-restricted group [3].
• Fetal weight was positively associated with maternal circulating IGF-II and negatively associated with maternal circulating IGFBP-1 and -2 [4].

High impact information on IGFBP1

• 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 [5].
• IGFBP-1, -2, -4, and -5 were of intermediate effectiveness as inhibitors, 3- to 11-fold less active than IGFBP-3 [6].
• Role of insulin-like growth factor binding protein (IGFBP)-3 in TGF-beta- and GDF-8 (myostatin)-induced suppression of proliferation in porcine embryonic myogenic cell cultures [7].
• We therefore determined whether glucose modulates IGFBP synthesis and stability in vitro [8].
• Evidence for an in vivo role of insulin-like growth factor-binding protein-1 and -2 as inhibitors of collagen gene expression in vitamin C-deficient and fasted guinea pigs [9].

Biological context of IGFBP1

• Assignment of the gene for porcine insulin-like growth factor binding protein 1 to chromosome 18 and detection of polymorphisms in intron 2 by PCR-RFLP [10].
• 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 [11].
• In contrast, mRNAs for IGFBP-1 and -2 and the circulating proteins were induced before or concomitantly with the suppression of collagen gene expression [9].
• Here we investigated the kinetics of induction of IGFBP-1 and -2 relative to suppression of collagen gene expression [9].
• The IGFBP also caused decreased rates of lipogenesis following a 1-hr preincubation of tissue with IGF-I (10(-8) M) [12].

Anatomical context of IGFBP1

• The IGFBP had no effect on insulin action on porcine adipose tissue [12].
• Activity of IGFBP-1 predominated in conditioned medium, and IGFBP-2 activity predominated in follicular fluid [1].
• Both experiments evaluated estradiol and IGFBP production by granulosa cells after separation of cells into subpopulations that maintain long-term estradiol production in vitro (tightly bound) and those that do not (weakly associated) [13].
• IGF-I, IGF-II, and IGF binding proteins (IGFBP) were characterized in porcine serum, colostrum, and milk on d 1-28 postpartum [14].
• Direct DNA injection into porcine skeletal muscle was investigated as an approach for studying roles of locally produced IGF-I on IGF-binding protein (IGFBP) production [15].

Associations of IGFBP1 with chemical compounds

• In conclusion, estradiol was most related to size of the follicle; however, lowering of IGF-I regardless of follicle diameter and alterations in IGFBP activity suggest that diabetes affects IGF-I and its binding proteins differently from estradiol production [1].
• Neither immunoneutralization of IGF-I nor OT substantially prevented the effects of GH on progesterone, IGFBP and PGE [16].
• The IGFBP protease activity of ULF may therefore comprise a group of enzymes including an unidentified serine protease [17].
• A large body of evidence suggests the existence of an intratesticular IGF system complete with ligands, receptors and binding proteins (IGFBPs); the aim of the present study was to evaluate tri-iodothyronine (T(3)) and retinoic acid (RA) effects on IGFBP production by Sertoli cells [18].
• Follicular fluid (FF) was collected from individual follicles; IGF-I and steroid hormone concentrations were determined by radioimmunoassay, and IGF-binding protein (IGFBP) expression was assessed by Western ligand blotting [19].

Physical interactions of IGFBP1

• During the final 48 h of culture, weakly associated cells produced greater quantities of 28-30-kDa IGFBP than did tightly bound cells in response to IGF-1 or analogs (both experiments; p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)[13]

Regulatory relationships of IGFBP1

• Growth hormone treatment stimulated secretion of each IGFBP by 47 +/- 4.7, 46 +/- 10.2, 70 +/- 13.2, and 49 +/- 5.6%, respectively, over control levels [20].

Other interactions of IGFBP1

• Inhibitory as well as stimulating controls of IGFBP-1 and -3 on IGF functions are discussed, which may maintain a balance between autocrine growth promoting activities of IGF-I and IGF1R [21].
• In uterine flushes, relaxin treatment increased an IGFBP doublet (33 and 34.5 kDa) and IGFBP-3 [22].
• However, in the presence of epidermal growth factor (which was without independent effect on the 30-kDa IGFBP), insulin also induced this 30-kDa IGFBP [23].
• Cultures were stained for morphological analysis and conditioned media were collected for IGF-1 determination by radioimmunoassay (RIA) and IGFBP analysis by Western blotting [24].
• In this study, we measured the effects of IGF-I, bFGF, and TGF-beta1 on IGFBP production by primary porcine satellite cell (PSC) cultures after first determining physiologically active concentrations of these growth factors to use according to [3H]thymidine incorporation dose responses [25].

Analytical, diagnostic and therapeutic context of IGFBP1

• The overall results taken together with our recent findings from cell culture experiments are compatible with circulating IGFBP-1 and -2 acting as inhibitors of collagen gene expression by blocking IGF-I action during fasting and phase II of vitamin C deficiency [9].
• The uterine IGFBP doublet was identified as IGFBP-2 by immunoprecipitation [22].
• Serum and milk were separated by isoelectric focusing into 20 fractions, across a gradient from pH 3 to 10, that were screened for IGFBP by Western ligand blotting [14].
• Western ligand blotting and immunoblotting were used to compare IGFBP levels in plasma and amniotic fluid [26].
• Quantities of IGF-I in medium were determined with a newly developed "titration" radioimmunoassay in which interference from IGFBP was minimized by adding a range of saturating quantities of IGF-II [27].

References