The role of somatomedin/insulin-like growth factors (Sm/IGFs) in neural growth and development is not clearly defined. To characterize Sm/IGF receptors and to correlate binding with the biologic actions of Sm/IGFs in a homogeneous population of neural cells, we isolated and studied a nearly pure population of cultured astroglial monolayers derived from cerebral cortices of neonatal rats. Bindin...

Hepatitis B virus infection is associated with acute and chronic liver disease and the development of hepatocellular carcinoma (hcc). Several lines of evidence have suggested that hepatitis B virus X protein (HBx), which is a transcriptional frans-activator, plays a role in the process of liver carcinogenesis. We have investigated the expression of insulin-like growth factor I (IGF-I) receptor ...

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 isofor...

Two types of receptors for insulin-like growth factors (IGFs) were characterized in glioma cell lines established from different human brain tumors of glial origin (astrocytoma grades III and IV) by competitive binding assay, affinity labeling, and protein phosphorylation. Type I IGF receptor is a heterodimer composed of alpha-subunits (Mr 130,000), which bind IGF I and II with equal affinity, ...

Human amniotic fluid has been shown to contain a protein that binds insulin-like growth factor I and II (IGF-I and IGF-II). Partially purified preparations of this protein have been reported to inhibit the biologic actions of the IGFs. In these studies our laboratory has used a modified purification procedure to obtain a homogeneous preparation of this protein as determined by polyacrylamide ge...

Nutritional status is a critical factor that modulates the responsiveness of the liver to GH and the resulting production of endocrine (mostly liver-derived) IGF-I. Using a conditional Cre/lox P system, we have established a liver-specific IGF-I-deficient mouse model. Despite the reduction in the circulating IGF-I (75%), the growth parameters are normal, except for the reduced spleen size, prov...

The relative contributions of type I and type II insulinlike growth factor (IGF) receptors and IGF carrier proteins to the binding of IGF-I tracer to cultured human fibroblasts were determined in competitive binding experiments that used unlabeled insulin and synthetic insulin-IGF-I hybrid molecules containing the A chain of insulin and the B domain of IGF-I. Whereas insulin binds only to type ...

Insulin-like growth factor (IGF) I is a polypeptide hormone important in normal growth and development. Although IGF-I is a mitogen for many cancer cell lines, previous work has suggested that autocrine production of IGF-I is uncommon in cancers of epithelial origin. In this study, expression of IGF-I, its binding proteins, and its receptor were examined in ovarian cancer cell lines and tissues...

The present study evaluated the ability of insulin-like growth factor I (IGF-I) complexed with IGF binding protein-3 (IGFBP-3) to modulate the sepsis-induced inhibition of protein synthesis in gastrocnemius. Beginning 16 h after the induction of sepsis, either the binary complex or saline was injected twice daily via a tail vein, with measurements made 3 and 5 days later. By day 3, sepsis had r...