The induction of specific proteases for insulin-like growth factor-binding proteins following major heart surgery

1992 ◽  
Vol 135 (1) ◽  
pp. 135-145 ◽  
Author(s):  
S. C. Cwyfan Hughes ◽  
A. M. Cotterill ◽  
A. R. Molloy ◽  
T. B. Cassell ◽  
N. Braude ◽  
...  
Keyword(s):  
Proteolytic Activity ◽  
Binding Proteins ◽  
Heart Surgery ◽  
Bypass Graft ◽  
Direct Result ◽  
Severe Illness ◽  
Igf I ◽  
Catabolic State ◽  
Vein Bypass ◽  
Igfbp 3

ABSTRACT Insulin-like growth factors (IGF-I and IGF-II) circulate bound to specific high-affinity binding proteins (IGFBPs). Recent evidence has shown that in pregnancy and severe illness, specific proteases modify these binding proteins, reducing their affinity for IGFs. We have studied 12 patients, undergoing elective coronary artery vein-bypass graft surgery, for the appearance of these proteases and have demonstrated the induction of two independent, heat-labile, cationdependent proteases. Proteolytic activity directed against IGFBP-3 was detected in all patients between 24 h and 5 days after surgery; the second IGFBP-4 specific protease was active 1 h after sternotomy. The total IGF-I levels were found to decrease following surgery, with the IGF-I distribution in the plasma being radically altered from that seen prior to the operation. One day after the operation the majority of the IGF-I, instead of being bound in the relatively inert 150 kDa complex, was associated with the smaller binding proteins which are more readily accessible to the tissues. These findings are in contrast to pregnancy where, despite similar proteases, the majority of the IGF-I remains in the 150 kDa complex. The alteration seen in IGF-I distribution after surgery did not appear to be a direct result of the IGFBP-3 proteolytic activity or an effect of the addition of heparin to the circulation. The potential increase in bioavailability of IGFs caused by the alteration in carrier protein may play a pivotal role in countering the catabolic state induced by surgery. Journal of Endocrinology (1992) 135, 135–145.

The induction of a specific protease for insulin-like growth factor binding protein-3 in the circulation during severe illness

1991 ◽  
Vol 130 (3) ◽  
pp. 469-NP ◽  
Author(s):  
S. C. Davies ◽  
J. A. H. Wass ◽  
R. J. M. Ross ◽  
A. M. Cotterill ◽  
C. R. Buchanan ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Specific Binding ◽  
Nitrogen Retention ◽  
Late Pregnancy ◽  
Severe Illness ◽  
Igf I ◽  
Catabolic State ◽  
Specific Protease ◽  
Circulating Levels ◽  
Igfbp 3

ABSTRACT The insulin-like growth factors (IGF-I and IGF-II) are almost completely bound in the circulation to specific binding proteins (IGFBPs). These IGFBPs appear to play a pivotal role in maintaining circulating levels and modulating the delivery of the IGFs to the tissues. A large proportion of the circulating IGFs are bound with high affinity to one of the binding proteins, IGFBP-3. The mechanism by which these IGFs are transferred from the circulatory pool to the tissue receptors is at present unclear. Recent studies in late pregnancy have demonstrated the presence of specific proteases which may modify the IGFBPs such that their affinities for the IGFs are reduced. In this paper, we have demonstrated the presence of a heat-sensitive cation-dependent proteolytic enzyme specific for IGFBP-3 in the serum of five severely ill patients. The activity of this protease was found to vary in these patients, becoming more apparent during fasting than when studied after commencement of parenteral nutrition, indicating that one of the influencing factors in the activity of this protease is the nutritional intake of the patient. Age- and sex-matched healthy adults were also studied in a similar protocol, but no proteolytic modification of any of the IGFBPs was found in any of the samples examined. As the levels of both IGF-I and IGF-II were found to be low in the patients, the presence of a circulatory protease suggests that this may be an adaptive response to increase the bioavailability of the IGFs and possibly to improve the nitrogen retention and counter the catabolic state in severe illness. Journal of Endocrinology (1991) 130,469–473

Measurement of Human Igf-II Using Sephacryl Extraction: A Rapid and Reliable Assay Method

1996 ◽  
Vol 33 (3) ◽  
pp. 201-208 ◽  
Author(s):  
Barbara H Mason ◽  
Michele A Tatnell ◽  
Ian M Holdaway
Keyword(s):  
Growth Factor ◽  
Binding Proteins ◽  
Complete Removal ◽  
Assay Method ◽  
Insulin Like Growth Factor ◽  
Serum Concentrations ◽  
Igf Binding Proteins ◽  
Factor Ii ◽  
Igf I ◽  
Igfbp 3

Measurement of insulin-like growth factor II (IGF-II) in human serum is complicated by the presence of IGF binding proteins and usually involves cumbersome extraction procedures followed by radioimmunoassay. We have utilized an extraction process developed for measuring insulin-like growth factor II in ovine serum using Sephacryl HR100, and have applied this to the extraction of human samples followed by radioimmunoassay for human IGF-II. The assay yielded 98% recovery of unlabelled IGF-II, parallelism between dilutions of eluate and the standard curve, complete removal of binding proteins and near-complete removal of IGF-I, and intra- and interassay coefficients of variation of 5% and 9%, respectively. The normal range for serum IGF-II in women was 490–1056 μg/L, and IGF-II levels were positively correlated with serum concentrations of insulin-like growth factor binding protein-3 (IGFBP-3) but not with IGF-I levels. Mean serum concentrations of IGF-II were reduced below normal in a number of hypopituitary patients and children with short stature and IGF-II concentrations in these subjects correlated positively with IGF-I and IGFBP-3. In acromegalic patients IGF-II levels were usually normal and were negatively correlated with IGF-I concentrations. From our experience with the above results the present assay appears particularly suitable for clinical measurements and research projects where high sample throughput is required.

Circulating insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs) and tissue mRNA levels of IGFBP-2 and IGFBP-4 in the ovine fetus

1995 ◽  
Vol 145 (3) ◽  
pp. 545-557 ◽  
Author(s):  
J M Carr ◽  
J A Owens ◽  
P A Grant ◽  
P E Walton ◽  
P C Owens ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Mrna Level ◽  
Common Factor ◽  
Late Gestation ◽  
Mrna Levels ◽  
Igf Binding Proteins ◽  
Fetal Sheep ◽  
Igf I ◽  
Igf Binding ◽  
Igfbp 3

Abstract The IGF-binding proteins (IGFBPs) are a family of at least six structurally related proteins, which bind the IGFs and modulate their actions, including the regulation of preand postnatal growth. In this study we have examined the relationship between circulating and tissue mRNA levels of IGFBPs and related this to circulating IGFs in the fetal sheep over the gestational period when rapid growth and development occurs. Circulating IGFBP-2, as measured by Western ligand blot (WLB), increases between early and mid gestation, remains high, then declines throughout late gestation (P=0·0002). Circulating IGFBP-3 increases throughout gestation, as measured by WLB or RIA (P=0·04 and P=0·0001 respectively), as does circulating IGFBP-4 (P=0·004). These ontogenic changes in circulating IGFBPs-2 and -4 are paralleled by changes in liver mRNA for these proteins and, for IGFBP-2, by those in kidney IGFBP-2 mRNA also. This suggests that liver and kidney may be the primary contributors to circulating IGFBP-2 and the liver to circulating IGFBP-4. IGFBP-2 mRNA is present in the heart and lung in early gestation but barely detectable in these tissues after approximately 60 days gestation. IGFBP-4 mRNA is also present in the heart in early but not late gestation, but is abundant in the lung throughout gestation. These results demonstrate tissue specific and developmental regulation of IGFBPs-2 and -4 at the mRNA level. To assess any role the circulating IGFs may play in mediating these changes in IGFBPs, or vice versa, both plasma IGF-I and IGF-II were measured by RIA. Circulating IGF-I increases as gestation progresses (P=0·0001), while circulating IGF-II increases between early and mid gestation, remains high (P=0·01), then declines. Circulating IGF-I is positively correlated with fetal weight (r=0·66, P=0·03), circulating IGFBP-3 (r=0·54, P=0·01) and IGFBP-4 (r=0·52, P=0·01). Circulating IGF-II positively correlates with circulating IGFBP-2 (r=0·48, P=0·02) throughout gestation and at 1 day postnatally. These relationships are consistent with circulating IGF-I influencing IGFBPs-3 and -4, and similarly, IGF-II determining IGFBP-2, or vice versa. Alternatively, these correlations may reflect coordinate regulation of IGF and IGFBP by a common factor. Journal of Endocrinology (1995) 145, 545–557

The insulin-like growth factors and their binding proteins in a case of non-islet-cell tumour-associated hypoglycaemia

1991 ◽  
Vol 131 (2) ◽  
pp. 303-311 ◽  
Author(s):  
A. M. Cotterill ◽  
J. M. P. Holly ◽  
S. C. Davies ◽  
V. J. Coulson ◽  
P. A. Price ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Islet Cell ◽  
Plasma Insulin ◽  
Binding Proteins ◽  
Late Pregnancy ◽  
Normal Serum ◽  
Systemic Effects ◽  
Igf Binding Proteins ◽  
Igf I ◽  
Igfbp 3

ABSTRACT Non-islet-cell tumours which induce hypoglycaemia are rare. Insulin-like growth factor-II (IGF-II) produced by some tumours is thought to be responsible for the hypoglycaemia and other systemic effects, despite normal or even low serum IGF-II levels. We studied a 44-year-old woman presenting with symptomatic hypoglycaemia associated with a large intraabdominal haemangiopericytoma. The serum IGF-II level was 455 μg/l when measured after acid-ethanol extraction (normal range (NR) 450–750 μg/l) and 1063 μg/l after acid chromatography (normal human serum pool 1068 μg/l). Levels of fasting plasma insulin, C-peptide, glucose and serum IGF-I levels were low before the operation (< 2 mU/l (NR <2-14), 0·23 nmol/l (NR 0-4-1-2), 3-1 mmol/l, (NR 3-7-5-9) and 002 U/ml respectively). After tumour removal, the symptoms resolved rapidly and the patient made a full recovery. Secretion of both insulin and growth hormone was suppressed before the operation in response to a 75 g glucose meal and to an infusion of 100 μg GH-releasing hormone (GHRH) respectively in comparison with studies after the operation. Serum IGF-II levels 6 weeks and 12 weeks after the operation fell to 385 μg/1 (777 μg/1; acid chromatography) and 280 μg/1 (647 μg/1; acid chromatography) and serum IGF-I levels increased to 0-35 U/ml and 0-26 U/ml. Serum before the operation and tumour extract contained chiefly a large molecular weight precursor IGF-II (molecular weight 15 000–20 000) which disappeared from the serum after the operation. The IGF-binding proteins (IGFBP-1, IGFBP-2, IGFBP-3 and IGFBP-4) were examined. The preoperation fasting serum IGFBP-1 level was lower than expected (31 μg/l (NR 20–70 μg/l)) and similar to levels at 6 weeks after the operation (33 μg/l). This was surprising given the differences in plasma insulin levels before and after the operation (< 2 mU/l versus 13 mU/l). Using Western ligand blotting techniques, serum IGFBP-3 levels were found to be low and IGFBP-2 appeared to be the dominant IGFBP before the operation. Serum IGFBP-3 levels after the operation fell further. This further decrease appeared, in part, to be due to the presence of a cation-dependent IGFBP-3-specific protease which has previously only been described in late pregnancy. We conclude that in this subject, despite normal serum IGF-II levels, the hypoglycaemia and systemic effects on insulin and GH secretion were due to increased bioavailability of a circulating tumour-produced precursor form of IGF-II. This increased bioavailability appears to be due to alterations in the circulating levels and perhaps affinities of the IGFBPs. Journal of Endocrinology (1991) 131, 303–311

Physical capacity influences the response of insulin-like growth factor and its binding proteins to training

2002 ◽  
Vol 93 (5) ◽  
pp. 1669-1675 ◽  
Author(s):  
Lars Rosendal ◽  
Henning Langberg ◽  
Allan Flyvbjerg ◽  
Jan Frystyk ◽  
Hans Ørskov ◽  
...  
Keyword(s):  
Growth Factor ◽  
Physical Training ◽  
Binding Proteins ◽  
Insulin Like Growth Factor ◽  
Initial Training ◽  
Serum Samples ◽  
Fitness Level ◽  
Igf System ◽  
Igf I ◽  
Igfbp 3

The influence of initial training status on the response of circulating insulin-like growth factor (IGF) and its binding proteins (IGFBP) to prolonged physical training was studied in young men. It was hypothesized that highly standardized training would result in more extensive changes in the circulating IGF system in untrained subjects because of lower fitness level. Seven untrained (UT) and 12 well-trained (WT) individuals performed 11 wk of intense physical training (2–4 h daily). Fasting serum samples were analyzed for total and free IGF-I and -II, for IGFBP-1 to -4, as well as for IGFBP-3 proteolysis. Eleven weeks of physical training resulted in decreased levels of total IGF-I, free IGF-I, and IGFBP-4 in both the UT and WT groups. In the UT group, IGFBP-2 increased, IGFBP-3 decreased [from 4,255 ± 410 (baseline) to 3,896 ± 465 (SD) μg/l ( week 4); P < 0.05], and IGFBP-3 proteolysis increased [from 28 ± 8% (baseline) to 37 ± 7% ( week 4) and 39 ± 12% ( week 11); P < 0.05], whereas no significant changes were found in the WT group. In conclusion, intense physical training results in a marked influence on the IGF system and its binding proteins with generally more extensive changes seen in the untrained individuals. Also, prolonged physical training resulted in increased IGFBP-3 proteolysis in previously untrained individuals only, indicating that intense physical training affects trained and untrained individuals differently.

scholarly journals IGF-I and IGF-I-binding proteins in rats with adjuvant-induced arthritis given recombinant human growth hormone

2000 ◽  
Vol 165 (3) ◽  
pp. 537-544 ◽  
Author(s):  
I Ibanez De Caceres ◽  
MA Villanua ◽  
L Soto ◽  
AI Martin ◽  
A Lopez-Calderon
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Binding Proteins ◽  
Body Weight Gain ◽  
Recombinant Human Growth Hormone ◽  
Gh Treatment ◽  
Adjuvant Induced Arthritis ◽  
Igf I ◽  
Igfbp 3

Adjuvant-induced arthritis in rats is associated with growth failure, hypermetabolism and accelerated protein breakdown. We have previously reported that adjuvant-induced arthritis in rats results in a decrease in body weight gain, pituitary GH mRNA, circulating GH and IGF-I together with an increase in serum IGF-binding proteins (IGFBPs). The aim of this study was to analyze the role of GH in the decrease in body weight and in the alterations in the IGF-I system observed in chronic inflammation. Male Wistar rats were injected with complete Freund's adjuvant and 16 days later arthritic rats were injected daily with recombinant human GH (rhGH) (3 IU/kg s.c.) for 8 days; control rats received 250 microl saline. Arthritis significantly decreased body weight gain and serum IGF-I. These decreases were not due to the reduced food intake, since in pair-fed rats they were not observed. Furthermore, administration of rhGH to arthritic rats increased body weight gain without modifying food intake. To further investigate the effect of GH administration, 14 days after adjuvant injection both control and arthritic rats were treated with 0, 1.5, 3 or 6 IU/kg of rhGH. GH treatment at the dose of 3 and 6 IU/kg significantly increased body weight gain in arthritic rats. GH administration, at the higher dose of 6 IU/kg, increased hepatic and serum concentrations of IGF-I in both control and arthritic rats. In control rats, rhGH at the three doses assayed increased circulating IGFBP-3. GH treatment in arthritic rats decreased IGFBP-1 and -2, and did not modify IGFBP-4. GH treatment at the dose of 3 IU/kg also decreased circulating IGFBP-3 in arthritic rats. These data suggest that GH treatment can ameliorate the catabolism observed in adjuvant-induced arthritis, an effect mediated, at least in part, by modifications in the circulating IGFBPs.

Associations of insulin-like growth factor binding proteins and adiponectin with disease progression and mortality in metastatic colorectal cancer: Results from CALGB/SWOG 80405 (Alliance).

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 3035-3035
Author(s):  
Brendan John Guercio ◽  
Alan P. Venook ◽  
Sui Zhang ◽  
Fang-Shu Ou ◽  
Donna Niedzwiecki ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Energy Balance ◽  
Metastatic Colorectal Cancer ◽  
Disease Progression ◽  
Binding Proteins ◽  
Linear Trend ◽  
C Peptide ◽  
All Cause Mortality ◽  
Igf I ◽  
Igfbp 3

3035 Background: Energy balance-associated biomarkers such as insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) have been associated with risk and prognosis of various malignancies. Their relationship to disease progression and mortality in metastatic colorectal cancer (mCRC) requires further study. Methods: In a prospective cohort study, baseline plasma IGFBP-3, IGFBP-7, C-peptide, IGF-I, and adiponectin were measured at trial registration among 1,086 patients participating in a National Cancer Institute-sponsored clinical trial of first-line therapy for mCRC. We used Cox proportional hazards regression to adjust for confounders and examine associations of biomarkers with overall (OS) and progression-free survival (PFS). Results: Higher plasma IGFBP-3 was associated with longer OS (adjusted Ptrend < .001) and PFS (adjusted Ptrend = .003). Compared to patients in the lowest IGFBP-3 quintile, patients in the highest quintile experienced an adjusted HR for all-cause mortality of 0.58 (95% CI 0.42 to 0.78) and for disease progression or mortality of 0.60 (95% CI 0.45 to 0.82). Higher plasma IGFBP-7 was associated with shorter OS (adjusted Ptrend < .001) and PFS (adjusted Ptrend = .02). Compared to patients in the lowest IGFBP-7 quintile, patients in the highest quintile experienced an adjusted HR for all-cause mortality of 1.52 (95% CI 1.24 to 1.88) and for disease progression or mortality of 1.28 (95% CI 1.05 to 1.57). C-peptide and IGF-I were not significantly associated with patient outcomes (adjusted Ptrend = .73 and .30 for OS). Adiponectin was not associated with OS; there was a U shaped association between adiponectin and PFS, wherein low and high values were associated with shorter PFS ( Pnon-linear trend = .03). Conclusions: In patients with mCRC, high plasma IGFBP-3 and low IGFBP-7 were associated with reduced risk of disease progression and mortality. These data suggest that energy-balance associated biomarkers may offer prognostic and biologic insights into mCRC. Support: U10CA180821, U10CA180882, BMS, Genentech, Pfizer, Sanofi; https://acknowledgments.alliancefound.org .

Differential effects of GH stimulation on fasting and prandial metabolism and plasma IGFs and IGF-binding proteins in lean and obese sheep

1997 ◽  
Vol 154 (2) ◽  
pp. 329-346 ◽  
Author(s):  
J P McCann ◽  
S C Loo ◽  
D L Aalseth ◽  
T Abribat
Keyword(s):  
Binding Proteins ◽  
Binding Capacity ◽  
Plasma Concentrations ◽  
Whole Body ◽  
Daily Injection ◽  
Gh Treatment ◽  
Igf Binding Proteins ◽  
Igf I ◽  
Igf Binding ◽  
Igfbp 3

Abstract The effect of body condition per se on plasma IGFs and IGF-binding proteins (IGFBPs) and the whole-body metabolic responses to recombinant DNA-derived bovine GH (rbGH) in both the fed and the fasted state were determined in lean and dietary obese sheep (n=6/group). Sheep at zero-energy balance and equilibrium body weight were injected s.c. for 12 days with 100 μg/kg rbGH immediately before their morning feeding. Before GH treatment, fasting plasma concentrations of insulin (17·0 ± 1·9 vs 7·5 ± 0·7 μU/ml), IGF-I (345 ± 25 vs 248 ± 10 ng/ml), glucose (52·6 ± 1·1 vs 48·3 ± 0·7 mg/dl), and free fatty acid (FFA) (355 ± 45 vs 229 ± 24 nmol/ml) were greater (P<0·05) and those of GH (1·1 ± 0·2 vs 2·6 ± 0·3 ng/ml) were lower (P<0·05) in obese than in lean sheep. Fasting concentrations of IGF-II and glucagon were not affected (P>0·05) by obesity. GH concentrations were increased equivalently by 6–9 ng/ml in lean and obese sheep during GH treatment. GH caused an immediate and a marked fivefold increase in the fasting insulin level in obese sheep but only minimally affected insulin concentration in lean sheep. The increment in fasting glucose during GH treatment was greater (P<0·05) in obese (8–12 mg/dl) than in lean (2–5 mg/dl) sheep. Frequent measurements in the first 8 h after feeding and injection of excipient (day 0) or the first (day 1), sixth (day 6) and twelfth (day 12) daily injection of GH showed that prandial metabolism in both groups of sheep was affected minimally by GH. However, GH treatment on day 1 (not days 6 or 12) acutely attenuated the feeding-induced suppression of plasma FFA in both groups of sheep and this effect was significantly greater in obese than in lean sheep. Although obese sheep were hyposomatotropic, the basal and GH-induced increases in plasma IGF-I concentrations were greater (P<0·05) in obese than in lean sheep. Plasma IGF-II was unaffected by obesity and was not increased by GH stimulation. Western ligand blotting showed that IGFBP-3 accounted for approximately 50–60% of the plasma IGF-I binding capacity in sheep respectively both before and during GH treatment. Basal plasma levels of IGFBP-2 were lower (P<0·05) and those of IGFBP-3 greater (P<0·05) in obese compared with lean sheep. GH increased the level of IGFBP-3 equally in lean and obese sheep, but suppressed the expression of IGFBP-2 more (P<0·05) in lean than in obese sheep. We concluded that the diabetogenic-like actions of GH in sheep were exaggerated markedly by obesity, and were expressed more during the fasted than the fed states. The effects of GH stimulation on the endocrine pancreas may be selective for β-cells and preferentially enhanced by obesity. GH regulation of IGF-I and the IGFBPs differs in lean and obese sheep. Journal of Endocrinology (1997) 154, 329–346

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