Changes in IGF-I receptor and IGF-I mRNA during differentiation of 3T3-L1 preadipocytes.
Insulin-like growth factor-1 (IGF-I) is an essential factor for the differentiation of preadipocytes into adipocytes. We investigated the expression of IGF-I receptor and IGF-I RNA messenger during 3T3-L1 preadipocyte differentiation. Levels of IGF-I receptor decreased in the mature adipocytes compared to cells before the initiation of differentiation. In addition, cultures not induced to differentiate showed a decrease on the receptor levels after 4 days in the presence of insulin compared to cultures without treatment. The levels of the IGF-I RNA messenger were shown to be higher in mature adipocytes compared to preadipocytes. We propose an autocrine and/or paracrine action of IGF-I in this adipocyte differentiation model, where IGF-I produced by the differentiating preadipocytes acts over their adjacent cells and, in this way, diminishes the expression of IGF-I receptor.
Zizola
Cynthia F
CF
Instituto de Biología y Medicina Experimental (CONICET), Vuelta de Obligado 2490, (1428), Buenos Aires, Argentina. cziola@dna.uba.ar
Balañá
María E
ME
Sandoval
Marcela
M
Calvo
Juan C
JC
D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000235:genetics* / Q000378:metabolism
D007328:Insulin; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1