Cycle modulation of insulin-like growth factor-binding protein 1 in human endometrium

AUTOR(ES)

Corleta, Helena von Eye

DATA DE PUBLICAÇÃO

2010

RESUMO

Endometrium is one of the fastest growing human tissues. Sex hormones, estrogen and progesterone, in interaction with several growth factors, control its growth and differentiation. Insulin-like growth factor 1 (IGF-1) interacts with cell surface receptors and also with specific soluble binding proteins. IGF-binding proteins (IGF-BP) have been shown to modulate IGF-1 action. Of six known isoforms, IGF-BP-1 has been characterized as a marker produced by endometrial stromal cells in the late secretory phase and in the decidua. In the current study, IGF-1-BP concentration and affinity in the proliferative and secretory phase of the menstrual cycle were measured. Endometrial samples were from patients of reproductive age with regular menstrual cycles and taking no steroid hormones. Cytosolic fractions were prepared and binding of 125I-labeled IGF-1 performed. Crosslinking reaction products were analyzed by SDS-polyacrylamide gel electrophoresis (7.5%) followed by autoradiography. 125I-IGF-1 affinity to cytosolic proteins was not statistically different between the proliferative and secretory endometrium. An approximately 35-kDa binding protein was identified when 125I-IGF-1 was cross-linked to cytosol proteins. Secretory endometrium had significantly more IGF-1- BP when compared to proliferative endometrium. The specificity of the cross-linking process was evaluated by the addition of 100 nM unlabeled IGF-1 or insulin. Unlabeled IGF-1 totally abolished the radioactivity from the band, indicating specific binding. Insulin had no apparent effect on the intensity of the labeled band. These results suggest that IGF-BP could modulate the action of IGF-1 throughout the menstrual cycle. It would be interesting to study this binding protein in other pathologic conditions of the endometrium such as adenocarcinomas and hyperplasia.

ASSUNTO(S)

igf-1 endometrio : metabolismo binding protein proteína 1 de ligação a fator de crescimento insulin-like endometrium

Documentos Relacionados

• Cycle modulation of insulin-like growth factor-binding protein 1 in human endometrium
• Insulin-like growth factor-binding protein-1 (IGFBP-1) mediates hypoxia-induced embryonic growth and developmental retardation
• Enhancing the Apoptotic Potential of Insulin-Like Growth Factor-Binding Protein-3 in Prostate Cancer by Modulation of CK2 Phosphorylation
• Protease-resistant form of insulin-like growth factor-binding protein 5 is an inhibitor of insulin-like growth factor-I actions on porcine smooth muscle cells in culture.
• Insulin-like growth factor-binding protein 5 (Igfbp5) compromises survival, growth, muscle development, and fertility in mice