Acute effects of insulin-like growth factor-I (IGF-I) on bone protein synthesis in rats

Martı́nez, Alfredo; Pascual, Mónica; Larralde, J

doi:10.1016/0304-4165(94)90103-1

Cited by 5 publications

(2 citation statements)

References 29 publications

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“…Although the results of our study may be somewhat limited by the cross-sectional study design and the various causes of OP, these results and past findings provide strong indirect evidence that alterations in circulating levels of IGF system components could, in part, contribute to the impairment of bone formation and associated bone loss in OP. The following lines of evidence support this concept: (i) stimulatory IGF system components were decreased in OP patients in this study, matching data from previous reports in patients with osteopenia and OP [13,15,16,21]; (ii) significant positive correlations have been reported between serum levels of stimulatory IGF system components and BMD, on the one hand [13,15,16], and bone histological osteoblastic surface, on the other hand [17]; and (iii) systemic administration of IGF-I, which increases circulating IGF-I levels, stimulates bone formation parameters in animal and human models [22,23].…”

Section: Discussionsupporting

confidence: 90%

Serum levels of insulin-like growth factor (IGF)-I and IGF binding protein (IGFBP)-1 to -6 and their relationship to bone metabolism in osteoporosis patients

Jehle

Schulten

Schulz

et al. 2003

European Journal of Internal Medicine

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BACKGROUND: Insulin-like growth factor (IGF) system components are important regulators of bone formation. Alterations of individual IGF system components have been described in osteoporosis (OP) patients; however, no study has addressed changes in free IGF-I and in all six IGF binding proteins (IGFBPs). METHODS: A cross-sectional study was performed in 45 OP patients and 100 healthy matched controls. Serum levels of free and total insulin-like growth factor I (IGF-I), IGFBP-1 through -6, intact parathyroid hormone (PTH), 25-OH-vitamin D(3) (25OHD(3)), 1,25-(OH)(2)-vitamin D(3) (1,25-(OH)(2)D(3)), osteocalcin (OSC), bone alkaline phosphatase (B-ALP), and carboxyterminal propeptide of type-I procollagen (PICP) were measured with specific assays. Bone mineral density (BMD) of the lumbar spine was determined by dual-energy X-ray absorptiometry (DEXA). RESULTS: Compared with age- and sex-matched control subjects, OP patients showed a 73% decrease in free IGF-I, a 29% decrease in total IGF-I, a 10% decrease in IGFBP-3, and a 52% decrease in IGFBP-5 levels; they had higher levels of IGFBP-1 (4.1-fold), IGFBP-2 (1.8-fold), IGFBP-4 (1.3-fold), and IGFBP-6 (2.1-fold). Alterations in IGF system components were most evident in 13 OP patients with vertebral fractures in the past 4 years compared to patients without fractures. In OP patients with fractures, the ratio between IGFBP-4 and IGFBP-5 was increased whereas levels of OSC were decreased. CONCLUSIONS: Our data provide strong indirect evidence for a functional connection between circulating IGF system components and bone metabolism and the susceptibility to fractures in OP patients.

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Section: Discussionsupporting

confidence: 90%

Serum levels of insulin-like growth factor (IGF)-I and IGF binding protein (IGFBP)-1 to -6 and their relationship to bone metabolism in osteoporosis patients

Jehle

Schulten

Schulz

et al. 2003

European Journal of Internal Medicine

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“…Serum IGF-I concentrations are nutritionally dependent (15,17) and decreased significantly after 4 d of fasting. Potent effects of IGF-I on osteoblast function and differentiation in vitro (2, 3, 5, 7) and bone protein synthesis and cancellous bone formation in animals and in humans have recently been demonstrated (29,38,39). Our finding of decreased serum and urine markers of bone turnover is consistent with biochemical data from other pathologic conditions associated with deficient IGF-I concentrations (25,28).…”

Section: Discussionsupporting

confidence: 87%

Effects of rhIGF-I administration on bone turnover during short-term fasting.

Grinspoon¹,

Baum²,

Peterson³

et al. 1995

J. Clin. Invest.

105

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IntroductionInsulin-like growth factor-I (IGF-I) is a nutritionally dependent bone trophic hormone which stimulates osteoblast function and collagen synthesis in vivo and in vitro. We hypothesized that in the fasting state, IGF-I levels would decline significantly and would establish a model in which we could investigate the effects of IGF-I administration on bone turnover. We therefore studied 14 normal women ages [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] 24±4 [SD] years) during a complete 10-d fast. After 4 d of fasting, subjects were randomized to receive rhIGF-I or placebo subcutaneously twice a day for 6 d. Bone turnover was assessed using specific markers of formation (osteocalcin and type I procollagen carboxyl-terminal propeptide [PICP]) and resorption (pyridinoline, deoxypyridinoline, type I collagen crosslinked N-telopeptide [N-telopeptide] and hydroxyproline). Serum levels of PICP and osteocalcin decreased from 143±52 to 60±28 ng/ml (P = 0.001) and from 7.6±5.4 to 4.2±3.1 ng/ml (P = 0.001) respectively with 4 d of fasting. Urinary excretion of pyridinoline and deoxypyridinoline decreased from 96±63 to 47±38 nmol/mmol creatinine (P < 0.05) and from 28±17 to 14±11 nmol/mmol creatinine (P < 0.05) respectively. Mean IGF-I levels decreased from 310±81 to 186±78 ng/ ml (P = 0.001).In the second part of the experimental protocol, serum osteocalcin and PICP levels increased 5-and 3-fold, respectively with rhIGF-I administration and were significantly elevated compared with the placebo group at the end of treatment (20.9±17.3 vs. 5.9±6.4 ng/ml for osteocalcin [P < 0.05] and 188±45 vs. 110±37 ng/ml for PICP [P < 0.05]). In contrast, all four markers of bone resorption, including urinary pyridinoline, deoxypyridinoline, N-telopeptide and hydroxyproline were unchanged with rhIGF-I administration. This report is the first to demonstrate that bone turnover falls rapidly with acute caloric deprivation in normal women. RhIGF-I administration uncouples bone formation in this setting by significantly increasing bone formation, but not resorption. These data suggest a novel use of rhIGF-I to selectively stimulate bone formation in states of undernutrition and low bone turnover. (J. Clin. Invest. 1995. 96:900-906.)

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Insulin-like growth factor I (IGF-I) affects plasma lipid profile and inhibits the lipolytic action of growth hormone (GH) in isolated adipocytes

1995

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Acute effects of insulin-like growth factor-I (IGF-I) on bone protein synthesis in rats

Cited by 5 publications

References 29 publications

Serum levels of insulin-like growth factor (IGF)-I and IGF binding protein (IGFBP)-1 to -6 and their relationship to bone metabolism in osteoporosis patients

Serum levels of insulin-like growth factor (IGF)-I and IGF binding protein (IGFBP)-1 to -6 and their relationship to bone metabolism in osteoporosis patients

Effects of rhIGF-I administration on bone turnover during short-term fasting.

Insulin-like growth factor I (IGF-I) affects plasma lipid profile and inhibits the lipolytic action of growth hormone (GH) in isolated adipocytes

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