Serum free IGF-I during a hyperinsulinemic clamp following 3 days of administration of IGF-I vs. saline.

1997 ◽  
Vol 273 (3) ◽  
pp. E507 ◽  
Author(s):  
J Frystyk ◽  
M Hussain ◽  
C Skjaerbaek ◽  
O Schmitz ◽  
J S Christiansen ◽  
...  
Keyword(s):  
Subcutaneous Administration ◽  
Serum Levels ◽  
Fasting Serum ◽  
Short Term ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Randomized Crossover Study ◽  
Igfbp 3

In a randomized crossover study in eight healthy subjects, we compared the effect of 3 days of continuous subcutaneous administration of insulin-like growth factor I (IGF-I; 10 micrograms.kg-1.h-1) and saline on fasting serum levels of free IGF-I, total (extractable) IGF-I, and IGF-binding protein (IGFBP)-1 and -3. On the 3rd day a hyperinsulinemic (euglycemic and hypoglycemic) clamp was performed. When preclamp (baseline) levels were compared after 3 days, IGF-I administration had increased total IGF-I from 225 +/- 21 (means +/- SE) to 1,003 +/- 46 micrograms/l (P < 0.0001), free IGF-I from 0.5 +/- 0.2 to 10.4 +/- 1.7 micrograms/l (P < 0.001), IGFBP-3 from 2,908 +/- 148 to 3,591 +/- 179 micrograms/l (P < 0.01), and IGFBP-1 from 7.6 +/- 3.8 to 19.6 +/- 2.5 micrograms/l (P < 0.01). During the clamp, levels of free IGF-I increased gradually from baseline to 1.0 +/- 0.3 micrograms/l (saline; P < 0.01) and to 19.6 +/- 4.7 micrograms/l (IGF-I; P < 0.005). Concomitantly, levels of IGFBP-1 decreased gradually from baseline to 4.1 +/- 2.3 micrograms/l (saline; P < 0.0005) and to 4.6 +/- 1.8 micrograms/l (IGF-I; P < 0.0001). Total IGF-I exhibited minor changes only during the clamp (P < 0.05), and IGFBP-3 was unchanged. In conclusion, administration of IGF-I increased total IGF-I about fourfold, whereas free IGF-I increased 20-fold. Noteworthily, in both situations a further twofold increase in free IGF-I was observed during the hyperinsulinemic clamp, concomitant with a decrease in IGFBP-1. This supports the hypothesis that IGFBP-1 is important in the short-term regulation of free IGF-I in vivo.

scholarly journals Abnormal Sex Chromosome Constitution and Longitudinal Growth: Serum Levels of Insulin-Like Growth Factor (IGF)-I, IGF Binding Protein-3, Luteinizing Hormone, and Testosterone in 109 Males with 47,XXY, 47,XYY, or Sex-Determining Region of the Y Chromosome (SRY)-Positive 46,XX Karyotypes

2008 ◽  
Vol 93 (1) ◽  
pp. 169-176 ◽  
Author(s):  
Lise Aksglaede ◽  
Niels E. Skakkebaek ◽  
Anders Juul
Keyword(s):  
Sex Chromosome ◽  
Serum Levels ◽  
Reproductive Hormones ◽  
Chromosome Constitution ◽  
Sitting Height ◽  
Igf I ◽  
Igf Binding ◽  
Xx Males ◽  
Igf Binding Protein ◽  
Igfbp 3

Abstract Context: Growth is a highly complex process regulated by the interaction between sex steroids and the GH IGF-axis. However, other factors such as sex chromosome-related genes play independent roles. Aim: The aim of the study was to evaluate the role of abnormal chromosome constitution for longitudinal growth in relation to reproductive hormones, IGF-I, and IGF binding protein (IGFBP)-3. Setting: The study was conducted at an outpatient clinic, Copenhagen University Hospital. Participants: Participants included 86 47,XXY males, 14 46,XX-males, and nine 47,XYY. Main Outcome Measures: Standing and sitting height, serum levels of reproductive hormones, IGF-I, and IGFBP-3 were measured. Results: In boys with 47,XXY and 47,XYY karyotypes, growth was accelerated already in childhood, compared with healthy boys. 46,XX-males were significantly shorter than healthy boys but matched the stature of healthy girls. In 47,XXY sitting height to height ratios were lower than expected, whereas body proportions in 46,XX-males and 47,XYY were normal. In all subjects serum levels of IGF-I and IGFBP-3 were within normal limits. The boys with 46,XX and 47,XXY karyotypes presented with low normal testosterone and elevated LH levels after puberty, whereas the sex hormone secretion of the 47,XYY boys remained normal. Conclusion: We found accelerated growth in early childhood in boys with 47,XXY and 47,XYY karyotypes, whereas 46,XX-males were shorter than controls. These abnormal growth patterns were not reflected in circulating levels of IGF-I and IGFBP-3. The boys with 46,XX and 47,XXY karyotypes developed hypogonadism in puberty, but androgen secretion in 47,XYY boys remained normal. The abnormal stature of these patients may be a result of abnormal gene expression due to the underlying chromosome aberration resulting in excessive expression of growth-related genes.

scholarly journals Insulin infusion increases levels of free IGF-I and IGFBP-3 proteolytic activity in patients after surgery

2001 ◽  
Vol 281 (4) ◽  
pp. E736-E741 ◽  
Author(s):  
J. Nygren ◽  
C. Carlsson-Skwirut ◽  
K. Brismar ◽  
A. Thorell ◽  
O. Ljungqvist ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
Growth Factor ◽  
Proteolytic Activity ◽  
Insulin Infusion ◽  
Serum Levels ◽  
Insulin Resistant ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

We have studied the effects of insulin on the bioavailability of insulin-like growth factor (IGF) I in insulin-resistant patients after surgery. Serum levels of total IGF-I (tIGF-I), free IGF (fIGF)-I, fIGF-II, and IGF-binding protein (IGFBP) 1 and IGFBP-3 proteolytic activity (IGFBP-3-PA), determined on the day before surgery and on the 1st postoperative day, were related to insulin sensitivity measured by a hyperinsulinemic, normoglycemic clamp. Before surgery, the decreased tIGF-I ( P < 0.05) in response to insulin infusion was accompanied by an 18% reduction of IGFBP-1 ( P < 0.001), while IGFBP-3-PA remained unchanged. Levels of fIGF-I and fIGF-II were not changed by insulin infusions. After surgery, IGFBP-3-PA increased ( P < 0.05) during insulin infusion, and this was associated with an increase in tIGF-I ( P < 0.001) and fIGF-I ( P < 0.01), while no significant change was found in fIGF-II. The reduction in IGFBP-1 in response to insulin infusion was not affected by surgery. The change in IGFBP-3-PA during insulin infusion after surgery was related to the corresponding change in fIGF-I ( r 2 = 0.26, P < 0.05) and postoperative insulin sensitivity ( r 2 = −0.22, P < 0.05). These data suggest that increased IGFBP-3-PA during insulin infusion after surgery governs the increased levels of fIGF-I, while insulin-induced suppression of IGFBP-1 was not affected by surgery. We propose that, in catabolic, postoperative patients, increased levels of insulin from exogenous or, possibly, endogenous sources (nutritionally induced) may be a signal to increase IGF-I bioavailability by increased expression of IGFBP-3-PA to counteract further deterioration in glucose metabolism.

scholarly journals Age-dependent changes in body composition in postmenopausal Japanese women: relationship to growth hormone secretion as well as serum levels of insulin-like growth factor (IGF)-I and IGF-binding protein-3

1998 ◽  
pp. 633-639 ◽  
Author(s):  
T Sugimoto ◽  
D Nakaoka ◽  
M Nasu ◽  
M Kanzawa ◽  
T Sugishita ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Body Composition ◽  
Growth Factor ◽  
Serum Levels ◽  
Japanese Women ◽  
Igf I ◽  
Age Dependent ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

The present study was performed to investigate the age-dependent changes in body composition and the possible role of growth hormone (GH), insulin-like growth factor (IGF)-I and IGF-binding protein-3 (IGFBP-3) in these changes in postmenopausal Japanese women. A total of 161 Japanese women aged 45-88 years (mean 62) were enrolled in the cross-sectional study. Body composition (bone mineral content (BMC), lean body mass (LBM) and fat) was measured by dual-energy X-ray absorptiometry, and the percentage of BMC, LBM and fat was calculated by dividing each absolute value of body composition by total body mass. Urinary GH concentration divided by creatinine in nocturnal urine samples collected just after waking was used as an index of endogenous GH secretion. Serum levels of IGF-I and IGFBP-3 were measured by RIA. Urinary GH levels as well as serum levels of IGF-I and IGFBP-3 declined with age. BMC, %BMC and LBM also declined with age, while fat mass and %fat did not obviously change with age. Urinary GH levels as well as serum levels of IGF-I and IGFBP-3 correlated positively with BMC, even if age was taken into account. On the other hand, urinary GH correlated negatively with fat and %fat. In contrast, serum levels of IGF-I and IGFBP-3 correlated positively with fat and %fat. LBM did not correlate with either urinary GH or serum IGFBP-3 levels but exhibited a weakly positive correlation with serum IGF-I level. The present study suggests that the GH-IGF-I-IGFBP-3 axis positively regulates bone mass, and that GH and IGF-I-IGFBP-3 inversely regulate fat mass, i.e. GH negatively and IGF-I-IGFBP-3 positively regulates it.

No evidence for reduced spontaneous or growth-hormone-stimulated serum levels of insulin-like growth factor (IGF)-I, IGF-II or IGF binding protein 3 in women with spinal osteoporosis

1994 ◽  
Vol 131 (2) ◽  
pp. 150-155 ◽  
Author(s):  
M Kassem ◽  
K Brixen ◽  
W Blum ◽  
L Mosekilde ◽  
EF Eriksen
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Binding Protein ◽  
Serum Levels ◽  
Insulin Like Growth Factor ◽  
Spinal Osteoporosis ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

Kassem M, Brixen K, Blum W, Mosekilde L, Eriksen EF. No evidence for reduced spontaneous or growth-hormone-stimulated serum levels of insulin-like growth factor (IGF)-I, IGF-II or IGF binding protein 3 in women with spinal osteoporosis. Eur J Endocrinol 1994;131:150–5. ISSN 0804–4643 To test the hypothesis that a dysfunctional growth hormone (GH)–insulin-like growth factor (IGF) axis may play a role in the pathogenesis of osteoporosis, we compared the levels of IGF-I, IGF-II and IGF binding protein 3 (IGFBP-3) in 15 women with spinal osteoporosis (i.e. at least one non-traumatic vertebral fracture) and 15 normal age-matched women. Furthermore, the response to 3 days' treatment with recombinant human GH (r-hGH) (0.2 IU kg−1·day−1) was determined. The basal levels of IGF-I, IGF-II and IGFBP-3 were similar in patients and controls (mean ± sem): IGF-I, 16.5 ± 1.3 versus 16.0 ± 1.3 nmol/l (NS); IGF-II, 79.9 ± 3.6 versus 72.5 ± 4.1 nmol/l (NS); and IGFBP-3, 125.7 ± 6.5 versus 130.3 ± 7.8 nmol/l (NS). Stimulation with r-hGH elicited increased levels of IGF-I, IGF-II and IGFBP-3 within both groups (p < 0.001). The maximal values expressed as a percentage of baseline were: IGF-I, 341 ± 26% versus 369 ± 22%, IGF-II, 125 ± 4% versus 119 ± 5%, IGFBP-3, 141 ± 5% versus 147 ± 7% in osteoporotic patients and controls, respectively. No significant differences were observed between patients and controls in either their maximal response or in the area under the response curves. Our results do not support the hypothesis of a dysfunctional GH–IGF axis in women with spinal osteoporosis. Kim Brixen, University Department of Endocrinology and Metabolism, Aarhus Amtssygehus, Tage-Hansens gade 2, DK-8000 Aarhus C, Denmark

scholarly journals The role of IGF binding protein-3 as a parameter of activity in acromegalic patients

1999 ◽  
pp. 145-148 ◽  
Author(s):  
I Halperin ◽  
R Casamitjana ◽  
L Flores ◽  
M Fernandez-Balsells ◽  
E Vilardell
Keyword(s):  
Binding Protein ◽  
Serum Levels ◽  
Glucose Load ◽  
Gh Secretion ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Normal Standard ◽  
Igfbp 3

OBJECTIVE: The production of insulin-like growth factor binding protein-3 (IGFBP-3), the main IGF-I binding protein, is regulated by GH, and its serum levels are increased in acromegaly. We investigated its potential value as a parameter of acromegaly activity or remission in comparison with IGF-I, taking GH suppression below 2 microg/l after glucose load as the normal standard. METHODS: Data from 40 acromegalic patients (12 males and 28 females, aged 28 to 79 years) were obtained retrospectively from stored samples. From these, 145 pairs of IGF-I/IGFBP-3 values were collected; in 67 of them, simultaneous measurement of GH after glucose loading allowed their classification as active or inactive acromegaly. Relationships between IGF-I, IGFBP-3 and GH after glucose load were assessed, as well as differences between IGF-I and IGFBP-3 levels in active and inactive acromegaly. RESULTS: Significant positive correlation between IGF-I and IGFBP-3 in 145 samples was observed (r=0.49, P<0. 0001). As for the 67 samples in which activity or remission could be defined in terms of GH after glucose load, 50 were active and 17 inactive. Both IGF-I and IGFBP-3 significantly correlated with minimum GH (r=0.53, P<0.0001 and r=0.41, P<0.001 respectively). For both parameters, significant differences of means between active and inactive cases were observed (623+/-296 vs 300+/-108 ng/ml, P<0.0001 for IGF-I, and 4.1+/-1.3 vs 3.2+/-0.9 microg/ml, P<0.006 for IGFBP-3). Yet, when comparing in individual cases their classification as active or inactive with the finding of normal or increased IGF-I and IGFBP-3, among active cases 16% appeared as normal according to IGF-I, and 50% appeared as normal in terms of IGFBP-3. Among inactive cases, 23.5% appeared as active according to IGF-I, while 17.5% appeared as active in terms of IGFBP-3. CONCLUSION: Even though IGFBP-3 reflects GH secretion, it offers no advantage over IGF-I in the assessment of acromegaly, and it may underestimate disease activity in acromegalic patients.

scholarly journals Mesenchymal IGF-I overexpression: paracrine effects in the intestine, distinct from endocrine actions

2002 ◽  
Vol 283 (4) ◽  
pp. G875-G885 ◽  
Author(s):  
Kristen L. Williams ◽  
C. Randall Fuller ◽  
James Fagin ◽  
P. Kay Lund
Keyword(s):  
Smooth Muscle Actin ◽  
Paracrine Effects ◽  
Igf I ◽  
Igf Binding ◽  
Actin Promoter ◽  
Mucosal Growth ◽  
Igf Binding Protein ◽  
Epithelial Growth ◽  
Igfbp 3

Local IGF-I expression is frequently increased in intestinal mesenchyme during adaptive growth of intestinal epithelium, but paracrine growth effects of IGF-I in vivo are not defined. We tested whether overexpression of IGF-I in intestinal mesenchyme increases epithelial growth and if effects are distinct from known effects of circulating IGF-I. SMP8-IGF-I-transgenic (TG) mice overexpress IGF-I driven by an α-smooth muscle actin promoter. Mucosal and muscularis growth were assessed in the jejunum, ileum, and colon of SMP8-IGF-I-TG mice and wild-type littermates. Abundance of the SMP8-IGF-I transgene and IGF binding protein (IGFBP)-3 and -5 mRNAs was determined. Mucosal growth was increased in SMP8-IGF-I-TG ileum but not jejunum or colon; muscularis growth was increased throughout the bowel. IGFBP-5 mRNA was increased in SMP8-IGF-I-TG jejunum and ileum and was specifically upregulated in ileal lamina propria. Overexpression of IGF-I in intestinal mesenchymal cells has preferential paracrine effects on the ileal mucosal epithelium and autocrine effects on the muscularis throughout the bowel. Locally expressed IGF-I has distinct actions on IGFBP expression compared with circulating IGF-I.

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