scholarly journals Dexamethasone administration attenuates the inhibitory effect of lipopolysaccharide on IGF-I and IGF-binding protein-3 in adult rats

2005 ◽  
Vol 185 (3) ◽  
pp. 467-476 ◽  
Author(s):  
Teresa Priego ◽  
Miriam Granado ◽  
Ana Isabel Martín ◽  
Asunción López-Calderón ◽  
María Angeles Villanúa
Keyword(s):  
Gene Expression ◽  
Inhibitory Effect ◽  
Mrna Levels ◽  
Serum Concentrations ◽  
Gh Receptor ◽  
Its Gene ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

The aim of this study was to investigate whether glucocorticoid administration had a beneficial effect on serum concentrations of insulin-like growth factor I (IGF-I) and on IGF-binding protein 3 (IGFBP-3) in rats injected with lipopolysaccharide (LPS). Adult male rats were injected with LPS or saline and pretreated with dexamethasone or saline. Dexamethasone administration decreased growth hormone (GH) receptor and IGF-I mRNA levels in the liver of control rats. LPS decreased GH receptor and IGF-I gene expression in the liver of saline-treated rats but not in the liver of dexamethasone-pretreated rats. In the kidney, GH receptor mRNA levels were not modified by dexamethasone or LPS treatment. However, LPS decreased renal IGF-I gene expression and dexamethasone pretreatment prevented this decrease. Serum concentrations of IGF-I were decreased by LPS, and dexamethasone pretreatment attenuated this effect. The gene expression of IGFBP-3 in the liver and kidney and its circulating levels were decreased by LPS. In control rats dexamethasone increased circulating IGFBP-3 and its gene expression in the liver, and decreased the proteolysis of this protein. Dexamethasone pretreatment attenuated the LPS-induced decrease in IGFBP-3 gene expression in the liver and prevented the LPS-induced decrease in IGFBP-3 gene expression in the kidney. Moreover, dexamethasone pretreatment attenuated the LPS-induced decrease in serum concentrations of IGFBP-3 and decreased the LPS-induced IGFBP-3 proteolysis in serum. In conclusion, dexamethasone pretreatment partially attenuates the inhibitory effect of LPS on serum IGF-I by blocking the decrease of its gene expression in the kidney as well as by attenuating the decrease in serum concentrations of IGFBP-3.

scholarly journals Endotoxin at low doses stimulates pituitary GH whereas it decreases IGF-I and IGF-binding protein-3 in rats

2003 ◽  
Vol 179 (1) ◽  
pp. 107-117 ◽  
Author(s):  
T Priego ◽  
M Granado ◽  
I Ibanez de Caceres ◽  
AI Martin ◽  
MA Villanua ◽  
...  
Keyword(s):  
Gene Expression ◽  
Inhibitory Effect ◽  
Low Doses ◽  
Serum Concentrations ◽  
Its Gene ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Higher Doses ◽  
Igfbp 3

While it is well known that sepsis inhibits serum IGF-I and its gene expression in the liver, the effect on pituitary GH and IGF-binding protein-3 (IGFBP-3) is poorly understood. The GH-IGF-I-IGFBP-3 response to different doses of lipopolysaccharide (LPS) administration has been investigated in adult male rats. Two experiments were performed, administration of low doses of LPS (5, 10, 50 and 100 microg/kg) and high doses of LPS (100, 250, 500 and 1000 microg/kg). Rats received two i.p. injections of LPS (at 1730 h and 0830 h the following day) and were killed 4 h after the second injection. LPS administration induced a biphasic response in serum concentrations of GH, with an increase at the 10 microg/kg dose, followed by a decrease at higher doses (100 microg/kg on up). Pituitary GH mRNA was also increased by the administration of 10 and 50 microg/kg LPS, whereas at higher doses LPS did not modify pituitary GH mRNA. We also analyzed the GH response to LPS in primary pituitary cell cultures. When exposed to LPS, in the culture medium, there was an increase in GH release at the concentration of 0.1 and 10 ng/ml, whereas more concentrated LPS did not modify GH release. Serum concentrations of IGF-I declined in a dose-dependent fashion after LPS administration in the rats injected with 10 microg/kg LPS on up. This decrease is secondary to modifications in its synthesis in the liver, since endotoxin injection decreased both IGF-I and its mRNA in the liver. The liver GH receptor mRNA was also decreased by LPS administration, but only in the animals injected with high LPS doses. There was a decrease in both the IGFBP-3 serum levels and its gene expression in the liver with all LPS doses studied. These data suggest a biphasic LPS effect on pituitary GH, a stimulatory effect at low doses and an inhibitory effect at higher doses, whereas it has a clear inhibitory effect on IGF-I and IGFBP-3 synthesis in the liver. The decrease in liver IGFBP-3 mRNA and in serum concentrations of IGFBP-3 in the rats injected with LPS may contribute to the decrease in serum concentrations of IGF-I.

scholarly journals Inactivation of Kupffer cells by gadolinium administration prevents lipopolysaccharide-induced decrease in liver insulin-like growth factor-I and IGF-binding protein-3 gene expression

2006 ◽  
Vol 188 (3) ◽  
pp. 503-511 ◽  
Author(s):  
M Granado ◽  
A I Martín ◽  
T Priego ◽  
M A Villanúa ◽  
A López-Calderón
Keyword(s):  
Gene Expression ◽  
Kupffer Cells ◽  
Inhibitory Effect ◽  
Gadolinium Chloride ◽  
Serum Concentrations ◽  
Tnf Α ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

Gram-negative bacterial infection or treatment of animals with bacterial lipopolysaccharide (LPS) induces a catabolic state with proteolysis, liver injury and an inhibition of the insulin-like growth factor-I (IGF-I) system. The purpose of this work was to elucidate the role of Kupffer cells in LPS-induced inhibition of the IGF-I/IGF-binding protein-3 (IGFBP-3) system. Adult male Wistar rats were either pretreated with the Kupffer cell inhibitor gadolinium chloride (10 mg/kg, i.v., 24 h prior to LPS exposure) or saline vehicle. Rats received two i.p. injections of 1 mg/kg LPS (at 17:30 and 08:30 h the following day) and were killed 4 h after the second injection. LPS administration induced a significant decrease in body weight and in serum concentrations of IGF-I and IGFBP-3 (P < 0.01), as well as in their gene expression in the liver. LPS-injected rats had increased serum concentrations of ACTH, corticosterone (P < 0.05), tumour necrosis factor-α (TNF-α) and nitrites (P < 0.01). Pretreatment of the animals with gadolinium chloride blocked the inhibitory effect of LPS on body weight, and on serum concentrations of IGF-I, IGFBP-3 and nitrites, as well as growth hormone receptor (GHR), IGF-I and IGFBP-3 gene expression in the liver. In contrast, gadolinium chloride administration did not modify the stimulatory effect of LPS on serum concentrations of ACTH, corticosterone and TNF-α. These results suggest that Kupffer cells are important mediators in the inhibitory effect of LPS on GHR, IGF-I and IGFBP-3 gene expression in the liver, leading to a decrease in serum concentrations of IGF-I and IGFBP-3.

NO plays a role in LPS-induced decreases in circulating IGF-I and IGFBP-3 and their gene expression in the liver

2004 ◽  
Vol 286 (1) ◽  
pp. E50-E56 ◽  
Author(s):  
Teresa Priego ◽  
Inmaculada Ibáñez de Cáceres ◽  
Ana Isabel Martín ◽  
M. Ángeles Villanúa ◽  
Asunción López-Calderón
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Serum Levels ◽  
Inhibitory Effect ◽  
Mrna Levels ◽  
Serum Concentrations ◽  
Igf I ◽  
Male Wistar Rats ◽  
Nitrite Nitrate ◽  
Igfbp 3

In this study, we administered aminoguanidine, a relatively selective inducible nitric oxide synthase (iNOS) inhibitor, to study the role of nitric oxide (NO) in LPS-induced decrease in IGF-I and IGFBP-3. Adult male Wistar rats were injected intraperitoneally with LPS (100 μg/kg), aminoguanidine (100 mg/kg), LPS plus aminoguanidine, or saline. Rats were injected at 1730 and 0830 the next day and killed 4 h after the last injection. LPS administration induced an increase in serum concentrations of nitrite/nitrate ( P < 0.01) and a decrease in serum concentrations of growth hormone (GH; P < 0.05) and IGF-I ( P < 0.01) as well as in liver IGF-I mRNA levels ( P < 0.05). The LPS-induced decrease in serum concentrations of IGF-I and liver IGF-I gene expression seems to be secondary to iNOS activation, since aminoguanidine administration prevented the effect of LPS on circulating IGF-I and its gene expression in the liver. In contrast, LPS-induced decrease in serum GH was not prevented by aminoguanidine administration. LPS injection decreased IGFBP-3 circulating levels ( P < 0.05) and its hepatic gene expression ( P < 0.01), but endotoxin did not modify the serum IGFBP-3 proteolysis rate. Aminoguanidine administration blocked the inhibitory effect of LPS on both IGFBP-3 serum levels and its hepatic mRNA levels. When aminoguanidine was administered alone, IGFBP-3 serum levels were increased ( P < 0.05), whereas its hepatic mRNA levels were decreased. This contrast can be explained by the decrease ( P < 0.05) in serum proteolysis of this binding protein caused by aminoguanidine. These data suggest that iNOS plays an important role in LPS-induced decrease in circulating IGF-I and IGFBP-3 by reducing IGF-I and IGFBP-3 gene expression in the liver.

Effect of high-protein feed supplements on concentrations of growth hormone (GH), insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 in plasma and on the amounts of GH and messenger RNA for GH in the pituitary glands of adult rams

1993 ◽  
Vol 138 (3) ◽  
pp. 421-427 ◽  
Author(s):  
I. J. Clarke ◽  
T. P. Fletcher ◽  
C. C. Pomares ◽  
J. H. G. Holmes ◽  
F. Dunshea ◽  
...  
Keyword(s):  
Binding Protein ◽  
Plasma Concentrations ◽  
High Protein ◽  
Mrna Levels ◽  
Igf I ◽  
Pituitary Glands ◽  
Igf Binding ◽  
Plasma Gh ◽  
Igf Binding Protein ◽  
Igfbp 3

ABSTRACT Three groups of mature rams were maintained on diets of hay, hay+2% lupin or hay+2% cowpea for 11 weeks. Serial blood samples were taken at 15-min intervals for 12 h for the determination of GH and IGF-I content by radioimmunoassay and for IGF-binding protein-3 (IGFBP-3) levels by Western blotting. The rams were killed after 77 days of supplementary feeding and their pituitary glands analysed for content of GH and GH mRNA. Mean plasma GH and baseline GH levels were significantly (P<0·01) decreased in the rams fed lupin and cowpea compared with controls fed hay and GH pulse amplitude was significantly (P<0·001) decreased in the group fed the cowpea diet. The frequency of GH pulses was not significantly altered by either treatment. Plasma concentrations of IGF-I were elevated in rams fed lupin (P<0·001) or cowpea (P<0·05). IGFBP-3 levels were not significantly (P>0·05) altered by either treatment. There were no significant differences in pituitary content of GH mRNA but pituitary content of GH was increased in rams fed lupin (P<0·05) and cowpea (P=0·07). In conclusion, a high-protein diet decreases plasma GH levels and increases IGF-I without changing plasma IGFBP-3 levels in rams. Thus ongoing synthesis of GH, as indicated by the mRNA levels, may cause a build up of GH stores in the pituitary gland. Journal of Endocrinology (1993) 138, 421–427

Role of IGF system of mitogens in the induction of fibroblast proliferation by keloid-derived keratinocytes in vitro

2003 ◽  
Vol 284 (4) ◽  
pp. C860-C869 ◽  
Author(s):  
Toan-Thang Phan ◽  
Ivor Jiun Lim ◽  
Boon Huat Bay ◽  
Robert Qi ◽  
Michael Thornton Longaker ◽  
...  
Keyword(s):  
Mrna Levels ◽  
Igf System ◽  
Normal Keratinocytes ◽  
Wound Healing Response ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

Keloids are proliferative dermal growths representing a pathological wound-healing response. We report high proliferation rates in normal (NF) and keloid-derived fibroblasts (KF) cocultured with keloid-derived keratinocytes (KK). IGF binding protein (IGFBP)-3 mRNA and secreted IGFBP-3 in conditioned media were increased in NF cocultured with KK compared with NF but markedly reduced in KF cocultured with KK or normal keratinocytes (NK). IGFBP-2 and IGFBP-4 mRNA levels were elevated, whereas IGFBP-5 mRNA was decreased in KF cocultured with KK or NK. Significant increases in IGFBP-2 and -4 mRNA in KF cocultured with KK did not correlate with protein secretion. Downstream IGF signaling cascade components, phospho-Raf, phospho-MEK1/2, phospho-MAPK, PI-3 kinase, phospho-Akt, and phospho-Elk-1, were elevated in KF cocultured with KK. Addition of recombinant human IGFBP-3 or antibodies against IGF-I or IGF-IR significantly inhibited proliferation of KF. The bioavailability of IGF-I may be related to the levels of IGFBP-3 produced, which in turn influences KF proliferation, suggesting that modulation of IGF-I, IGF-IR, and IGFBP-3, individually or in combination, may represent novel approaches to the treatment of keloids.

Reduction in circulating IGF-I and hepatic IGF-I mRNA levels after caecal ligation and puncture are associated with differential regulation of hepatic IGF-binding protein-1, -2 and -3 mRNA levels

1996 ◽  
Vol 151 (2) ◽  
pp. 287-292 ◽  
Author(s):  
J Rodríguez-Arnao ◽  
G Yarwood ◽  
C Ferguson ◽  
J Miell ◽  
C J Hinds ◽  
...  
Keyword(s):  
Food Intake ◽  
Surgical Stress ◽  
Differential Regulation ◽  
Mrna Levels ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Caecal Ligation And Puncture ◽  
Igfbp 3 ◽  
Caecal Ligation

Abstract Sepsis is characterized by a severe shift in metabolism, characterized by low IGF-I levels. We have studied the influence of caecal ligation and puncture (CLP) on the levels of circulating IGF-I and hepatic IGF-I and IGF-binding protein (IGFBP)-1, -2 and -3 mRNA in adult male Wistar rats (n=12) and compared it with sham-operated rats (n=6). In order to exclude anorexia-induced changes we also studied animals pair-fed to both groups. IGF-I levels were measured by RIA. Steady-state hepatic IGF-I, IGFBP-1, IGFBP-2 and IGFBP-3 mRNA levels were measured by Northern blot analysis using specific rat cDNA probes. Food intake averaged 13·0 ± 2·0 g/day in the sham-operated rats fed ad libitum during the study period, with a sharp decline in food intake in the CLP animals (2·3 ± 1·3 g/day). After CLP, there was a significant reduction in circulating IGF-I levels (467·2 ± 50·9 μg/l) compared with sham-operated animals (924·0 ± 75·3 μg/l; P=0·04) or those pair-fed to the CLP rats (612·5 ± 52·9 μg/l; P=0·04). Total hepatic IGF-I mRNA levels were significantly reduced (2·57 ± 0·05 densitometric units (DU)) after CLP compared with the sham-operated group (2·71 ± 0·04; P=0·04), or their pair-fed controls (2·75 ± 0·08 DU; P<0·05). Hepatic IGFBP-3 mRNA levels were lower after CLP (0·37 ± 0·04 DU) than in the sham-operated animals (0·66 ± 0·09 DU; P=0·04) or their pair-fed controls (0·61 ± 0·05 DU; P=0·04). On the other hand, hepatic IGFBP-2 mRNA levels were increased after CLP (0·91 ± 0·11 DU) compared with sham-operated animals (0·28 ± 0·06 DU; P=0·01) or with their pair-fed controls (0·22 ± 0·22; P=0·01), as were hepatic IGFBP-1 mRNA levels (CLP animals 0·95 ± 0·11 DU; sham-operated 0·30 ± 0·04 DU, P=0·01; pair-fed 0·30 ± 0·02 DU, P=0·01). No significant difference between sham-operated animals and their pair-fed controls was observed in circulating IGF-I levels (888·0 ± 109·3 μg/l; P=not significant (N.S.)), hepatic mRNA levels for IGF-I (2·72 ± 0·06 DU; P=N.S), IGFBP-3 (0·71 ± 0·07 DU; P=N.S.), IGFBP-2 (0·25 ± 0·07 DU; P=N.S.) or IGFBP-1 (0·27 ± 0·06 DU; P=N.S.). In summary, after CLP there was a reduction in both circulating and hepatic IGF-I mRNA levels associated with a specific and differential regulation of hepatic IGFBP-1, -2 and -3 mRNA levels. Although we cannot eliminate a possible effect of surgical stress combined with malnutrition, our results suggest that these changes are a specific effect of sepsis rather than simply a result of surgical stress or poor nutrition alone. Journal of Endocrinology (1996) 151, 287–292

scholarly journals Effect of chronic thyroxine treatment on IGF-I, IGF-II and IGF-binding protein expression in mammary gland and liver during pregnancy and early lactation in rats

2002 ◽  
pp. 729-739 ◽  
Author(s):  
R Rosato ◽  
D Lindenbergh-Kortleve ◽  
J Neck ◽  
S Drop ◽  
G Jahn
Keyword(s):  
Mammary Gland ◽  
Binding Protein ◽  
Mammary Development ◽  
Mammary Tissue ◽  
Mrna Levels ◽  
Liver Growth ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

OBJECTIVE: Hyperthyroidism in rats produces organ hypertrophy and increases in circulating IGF-I and IGF-binding protein (IGFBP)-3. Chronic treatment with thyroxine (T(4)) during pregnancy advances parturition, blocks lactation and changes several hormone receptors in mammary gland and liver. Since IGFs are implicated in mammary and liver growth and in differentiation, we studied the effects of hyperthyroidism, induced by daily injections of T(4) (0.25 mg/kg). DESIGN AND METHODS: Using quantitative RT-PCR and in situ hybridization, the gene expression of IGF-I, IGF-II and the IGFBPs was determined in mammary gland and liver of rats at estrus and days 7, 14 and 21 of pregnancy (G7, G14, G21), day 1 postpartum (L1) and 3 days after removing the litter (L4). Circulating levels of IGF-I, tri-iodothyronine (T(3)), PRL and GH were measured. RESULTS: T(4) treatment (HT) increased circulating T(3) save on G21, did not change serum IGF-I, increased PRL on G21 and decreased GH on L1. PRL decreased on L1 because of the absence of lactation. Hepatic IGF-I mRNA was low during pregnancy and increased on L4. HT advanced this increase to L1. In controls, liver IGFBP-3 mRNA levels decreased from G14 to G21, whereas IGFBP-4 showed an inverse pattern. HT lowered IGFBP-3 mRNA and increased IGFBP-4. Increases in mammary concentrations of IGF-I, IGFBP-3 and IGFBP-4 mRNAs were seen on G21. HT delayed these peaks to L1. Mammary IGF-II and IGFBP-2 mRNA levels were high on G7 and G14, and fell afterwards, with HT having no effects. IGFBP-5 mRNA decreased during pregnancy and increased on L1. HT increased IGFBP-5 levels in early pregnancy and on L1. IGF-I mRNA localized to connective and epithelial mammary tissue, while IGFBP-2 and IGFBP-5 mRNA was only in epithelial cells. CONCLUSION: These results imply a role for IGF-I, IGFBP-3 and IGFBP-4 in terminal mammary development, while IGF-II and IGFBP-2 may be implicated in early growth. IGFBP-5 has been implicated in mammary apoptosis, and the HT-induced increase may play a role in the premature mammary involution of the HT rats.

scholarly journals Interactions between the ovary and the local IGF-I axis modulate mammary development in prepubertal heifers

2003 ◽  
Vol 177 (2) ◽  
pp. 295-304 ◽  
Author(s):  
SD Berry ◽  
RD Howard ◽  
PM Jobst ◽  
H Jiang ◽  
RM Akers
Keyword(s):  
Mrna Expression ◽  
Specific Binding ◽  
Mammary Development ◽  
Serum Concentrations ◽  
Fat Pad ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Local Expression ◽  
Igfbp 3

The objective was to determine the effects of ovariectomy and epithelial-stromal interactions on mammary development and local expression of IGF-I and IGF-binding protein (IGFBP) mRNA in prepubertal heifers. An epithelium-free ('cleared') fat pad (CFP) was prepared in two glands in each of 14 Holstein heifers, aged 1-3 Months. Eight of the calves were also ovariectomized. Serum concentrations of GH, IGF-I and prolactin were not affected by ovariectomy. At 6 Months of age, calves were killed to provide mammary samples of parenchyma, CFP and intact fat pad (MFP). Total mammary mass was reduced in ovariectomized calves (130+/-21 g vs 304+/- 25 g; P<0.001), and in several cases parenchymal tIssue was essentially absent. Uterus weight was also reduced by ovariectomy (14.5+/-3.8 g vs 30.4+/-4.5 g; P<0.05). In support of our hypothesis that local IGF-I mediates prepubertal mammary development, mRNA expression of IGF-I was lower in ovariectomized than in control calves (62.1+/-7.8 vs 91.6+/-7.8 arbitrary units; P<0.05). Specific binding of IGF-I to mammary parenchymal microsomes was also reduced by ovariectomy (377+/-142 vs 868+/-82 c.p.m.; P<0.01), suggesting decreased sensitivity to IGF-I. Expression of IGFBP-3 and IGFBP-5 mRNA were not influenced by ovariectomy. Expression of IGF-I, IGFBP-3 and IGFBP-5 mRNA did not differ between CFP and MFP, suggesting that expression of these factors was not influenced by interactions between stroma and developing epithelium. Overall, the data suggested that interactions between the ovary and the local IGF-I axis act to optimize the availability and effectiveness of IGF-I within the gland to stimulate mammary growth.

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