scholarly journals Growth Hormone (GH) or Insulin-like Growth Factor (IGF)-I Represses 11β-Hydroxysteroid Dehydrogenase Type 1 (HSD1) mRNA Expression in 3T3-L1 Cells and Its Activity in Their Homogenates

2009 ◽  
Vol 56 (4) ◽  
pp. 561-570 ◽  
Author(s):  
Junko MORITA ◽  
Fumihiko HAKUNO ◽  
Naomi HIZUKA ◽  
Shin-ichiro TAKAHASHI ◽  
Kazue TAKANO
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Mrna Expression ◽  
Hydroxysteroid Dehydrogenase ◽  
Insulin Like Growth Factor ◽  
Igf I

Effects of refeeding of undernourished and insulin treatment of diabetic neonatal rats on IGF and IGFBP

1996 ◽  
Vol 271 (2) ◽  
pp. E223-E231 ◽  
Author(s):  
L. Goya ◽  
F. Rivero ◽  
M. A. Martin ◽  
R. Arahuetes ◽  
E. R. Hernandez ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Body Weight ◽  
Growth Factor ◽  
Mrna Expression ◽  
Insulin Treatment ◽  
Diabetic Rats ◽  
Insulin Like Growth Factor ◽  
Neonatal Rats ◽  
Igf I ◽  
Serum Gh

The effect of refeeding and insulin treatment of undernourished and diabetic neonatal rats, respectively, on the regulation of insulin-like growth factor (IGF) and insulin-like growth factor binding protein (IGFBP) was investigated. The changes in body weight, insulinemia, glycemia, serum IGF-I, and growth hormone (GH) as well as the increase of the 30-kDa IGFBP in undernourished and diabetic neonatal rats previously shown elsewhere were reversed by refeeding and insulin treatment, respectively. Also, changes in liver mRNA expression of IGF-I and-II and IGFBP-1 and -2 were restored in refed undernourished and IGF-I and IGFBP-1 levels recovered in insulin-treated diabetic rats. However, serum GH was still below normal after rehabilitation in both situations. Thus the present results support the idea of a GH-independent IGF/ IGFBP regulation mediated by a balance of insulin and nutrients as has already been suggested in previous neonatal studies.

scholarly journals Estrogen modulates osteoblast proliferation and function regulated by parathyroid hormone in osteoblastic SaOS-2 cells: role of insulin-like growth factor (IGF)-I and IGF-binding protein-5

2000 ◽  
Vol 167 (2) ◽  
pp. 305-313 ◽  
Author(s):  
M Nasu ◽  
T Sugimoto ◽  
H Kaji ◽  
K Chihara
Keyword(s):  
Parathyroid Hormone ◽  
Growth Factor ◽  
Mrna Expression ◽  
Insulin Like Growth Factor ◽  
Osteoblast Proliferation ◽  
Igf I ◽  
Igf Binding ◽  
And Function ◽  
Igf Binding Protein

Although there is clinical evidence showing that combined therapy with parathyroid hormone (PTH) and estrogen is additively effective in increasing the bone mass of patients with osteoporosis, the mechanism of the interaction between these hormones remains unclear. The present study was performed to determine whether estrogen would affect osteoblast proliferation and function modulated by PTH in human osteoblastic SaOS-2 cells. Human PTH-(1-34) significantly inhibited [(3)H]thymidine (TdR) incorporation, which was attenuated by 24 h pretreatment with 10(-10) to 10(-7) M 17 beta-estradiol (17 beta-E(2)) in a concentration-dependent manner. PTH significantly stimulated alkaline phosphatase (ALP) activity, collagen synthesis and type-1 procollagen mRNA expression after pretreatment with 17 beta-E(2 )in these cells. Tamoxifen, an anti-estrogen, antagonized these 17 beta-E(2)-induced effects. Pretreatment with insulin-like growth factor-I (IGF-I) mimicked estrogen action, and coincubation of 3 microg/ml anti-IGF-I antibody antagonized the effects of 17 beta-E(2 )as well as those of IGF-I. In the presence of 17 beta-E(2 )pretreatment, PTH strongly stimulated IGF-binding protein (IGFBP)-5 mRNA expression in these cells, and recombinant IGFBP-5 increased type-1 procollagen mRNA expression and ALP activity. In conclusion, estrogen attenuates PTH-induced inhibition of osteoblast proliferation and PTH stimulates osteoblast function in the presence of estrogen pretreatment. IGF-I and/or IGFBP-5 seemed to be involved in the estrogen-induced modulation of PTH action on osteoblast proliferation and function.

Alterations of growth plate and abnormal insulin-like growth factor I metabolism in growth-retarded hypokalemic rats: effect of growth hormone treatment

2009 ◽  
Vol 297 (3) ◽  
pp. F639-F645 ◽  
Author(s):  
Helena Gil-Peña ◽  
Enrique Garcia-Lopez ◽  
Oscar Alvarez-Garcia ◽  
Vanessa Loredo ◽  
Eduardo Carbajo-Perez ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Mrna Expression ◽  
Growth Plate ◽  
Female Rats ◽  
Insulin Like Growth Factor ◽  
Gh Treatment ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Hypokalemic tubular disorders may lead to growth retardation which is resistant to growth hormone (GH) treatment. The mechanism of these alterations is unknown. Weaning female rats were grouped ( n = 10) in control, potassium-depleted (KD), KD treated with intraperitoneal GH at 3.3 mg·kg−1·day−1 during the last week (KDGH), and control pair-fed with KD (CPF). After 2 wk, KD rats were growth retarded compared with CPF rats, the osseous front advance (±SD) being 67.07 ± 10.44 and 81.56 ± 12.70 μm/day, respectively. GH treatment did not accelerate growth rate. The tibial growth plate of KD rats had marked morphological alterations: lower heights of growth cartilage (228.26 ± 23.58 μm), hypertrophic zone (123.68 ± 13.49 μm), and terminal chondrocytes (20.8 ± 2.39 μm) than normokalemic CPF (264.21 ± 21.77, 153.18 ± 15.80, and 24.21 ± 5.86 μm). GH administration normalized these changes except for the distal chondrocyte height. Quantitative PCR of insulin-like growth factor I (IGF-I), IGF-I receptor, and GH receptor genes in KD growth plates showed downregulation of IGF-I and upregulation of IGF-I receptor mRNAs, without changes in their distribution as analyzed by immunohistochemistry and in situ hybridization. GH did not further modify IGF-I mRNA expression. KD rats had normal hepatic IGF-I mRNA levels and low serum IGF-I values. GH increased liver IGF-I mRNA, but circulating IGF-I levels remained reduced. This study discloses the structural and molecular alterations induced by potassium depletion on the growth plate and shows that the lack of response to GH administration is associated with persistence of the disturbed process of chondrocyte hypertrophy and depressed mRNA expression of local IGF-I in the growth plate.

Somatostatin inhibits hepatic growth hormone receptor and insulin-like growth factor I mRNA expression by activating the ERK and PI3K signaling pathways

2008 ◽  
Vol 295 (2) ◽  
pp. R490-R497 ◽  
Author(s):  
Alison L. Hagemeister ◽  
Mark A. Sheridan
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Protein Kinase ◽  
Mrna Expression ◽  
Growth Hormone Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Previously, we reported that somatostatins (SS) inhibit organismal growth by reducing hepatic growth hormone (GH) sensitivity and by inhibiting insulin-like growth factor I (IGF-I) production. In this study, we used hepatocytes isolated from rainbow trout to elucidate the mechanism(s) associated with the extrapituitary growth-inhibiting actions of SS. SS-14, a predominant SS isoform, stimulated tyrosine phosphorylation of several endogenous proteins, including extracellular signal-regulated kinase (ERK), a member the mitogen-activated protein kinase (MAPK) family, and protein kinase B (Akt), a downstream target of phosphatidylinositol 3-kinase (PI3K). SS-14 specifically stimulated the phosphorylation of both ERK 1/2 and Akt in a concentration-dependent fashion. This activation occurred within 5–15 min, then subsided after 1 h. The ERK inhibitor U0126 retarded SS-14-stimulated phosphorylation of ERK 1/2, whereas the PI3K inhibitor LY294002 blocked SS-14-stimulated phosphorylation of Akt. SS-14-inhibited expression of GH receptor (GHR) mRNA was blocked by U0126 but not by LY294002. By contrast, U1026 had no effect on SS-14 inhibition of GH-stimulated IGF-I mRNA expression, whereas LY294002 partially blocked the inhibition of GH-stimulated IGF-I mRNA expression by SS-14. These results indicate that SS-14-inhibited GHR expression is mediated by the ERK signaling pathway and that the PI3K/Akt pathway mediates, at least in part, SS-14 inhibition of GH-stimulated IGF-I expression.

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