Document Detail


Insulin and insulin-like growth factor I signaling pathways in rainbow trout (Oncorhynchus mykiss) during adipogenesis and their implication in glucose uptake.
MedLine Citation:
PMID:  20237304     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Primary cultures of rainbow trout (Oncorhynchus mykiss) adipocytes were used to examine the main signaling pathways of insulin and insulin-like growth factor I (IGF-I) during adipogenesis. We first determined the presence of IGF-I receptors (IGF-IR) and insulin receptors (IR) in trout preadipocytes (day 5) and adipocytes (day 14). IGF-IRs were more abundant and appeared to be in higher levels in differentiated cells than in preadipocytes, whereas IRs were detected in lower but constant levels throughout the culture. The cells were immunoreactive against ERK1/2 MAPK, and AKT/PI3K, components of the two main signal transduction pathways for insulin and IGF-I receptors. Stimulation of MAPK phosphorylation by IGF-I was higher in preadipocytes than in adipocytes, while no effects were observed in MAPK phosphorylation after incubation of cells with insulin. AKT phosphorylation increased in the presence of both insulin and IGF-I, with higher levels of stimulation in adipocytes than in preadipocytes. Activation of both pathways was blocked by the use of specific inhibitors of MAPK (PD98059) and AKT (wortmannin). We describe here, for the first time, the effects of IGF-I and insulin on 2-deoxyglucose uptake in primary culture of trout adipocytes. IGF-I was more potent in stimulating glucose uptake than insulin, and PD98059 and wortmannin inhibited the stimulation of glucose uptake by this growth factor, suggesting that IGF-I plays an important metabolic role in trout adipocytes. Our results suggest that differential activation of the MAPK and AKT pathways are involved in the IGF-I- and insulin-induced effects of trout adipocytes during the various stages of adipogenesis.
Authors:
L Bouraoui; E Capilla; J Gutiérrez; I Navarro
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-03-17
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  299     ISSN:  1522-1490     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-06-25     Completed Date:  2010-07-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R33-41     Citation Subset:  IM    
Affiliation:
Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.
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MeSH Terms
Descriptor/Qualifier:
Adipocytes / cytology*,  metabolism
Adipogenesis / drug effects
Animals
Biological Transport / drug effects
Cell Differentiation / drug effects,  physiology
Deoxyglucose / metabolism
Flavonoids
Glucose / pharmacology
Hormones / pharmacology
Insulin / metabolism*
Insulin-Like Growth Factor I / metabolism*
Oncorhynchus mykiss / metabolism*
Phosphorylation / drug effects
Proto-Oncogene Proteins c-akt / metabolism
Receptor, IGF Type 1 / metabolism,  physiology
Receptor, Insulin / metabolism
Signal Transduction / physiology*
Chemical
Reg. No./Substance:
0/Flavonoids; 0/Hormones; 0/PD 98059; 11061-68-0/Insulin; 154-17-6/Deoxyglucose; 50-99-7/Glucose; 67763-96-6/Insulin-Like Growth Factor I; EC 2.7.10.1/Receptor, IGF Type 1; EC 2.7.10.1/Receptor, Insulin; EC 2.7.11.1/Proto-Oncogene Proteins c-akt

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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