The present study shows that insulin-like growth factor I (IGF-I) and FSH receptor (FSHR) mRNAs are selectively coexpressed in a subset of healthy-appearing follicles in murine ovaries, irrespective of cycle stage. Aromatase gene expression, a prime marker for FSH effect, is found only in IGF-I/FSHR-positive follicles, showing that these are healthy, gonadotropin-responsive follicles. Given the...

The insulin receptor (IR) form hybrids with the closely related insulin-like growth factor-I (IGF-I) receptor (IGF-I-R). Because most human breast carcinomas overexpress both the IR and the IGF-I-R, we evaluated whether the insulin/IGF-I hybrid receptor (Hybrid-R) is also overexpressed in these tumors and what role it plays in breast cancer biology. Using specific ELISAs and Western blots, we m...

Insulin-like growth factor-I (IGF-I) plays an important role in regulating vascular smooth muscle cell (VSMC) proliferation and directed migration. The mitogenic and chemotactic actions of IGF-I are mediated through the IGF-I receptor, but how the activation of the IGF-I receptor leads to these biological responses is poorly understood. In this study, we examined the role of phosphatidylinosito...

Interactions between insulin-like growth factor I (IGF-I) and the type of I IGF receptor may be affected by high-affinity extracellular binding proteins. To date, six distinct IGF binding proteins (IGFBPs) have been identified, but their physiological roles are not well understood. For example, depending on experimental conditions, IGFBP-1 has been shown to both enhance and inhibit IGF-I mediat...

Insulin-like growth factor-I and -II (IGF-I and IGF-II), both of which bind to type I IGF receptors, can modulate certain functions of the immune system. We, therefore, studied the expression of type I IGF receptors on purified subpopulations of peripheral blood mononuclear cells. Using two-color flow cytometry, specific binding of a monoclonal antibody directed against the type I IGF receptor ...

Differentiation of Tera-2 human embryonal carcinoma cells by exposure to 2.1 mM alpha-difluoromethylornithine resulted in changes in morphology, a decrease in growth rate, and changes in the expression of SSEA-1 differentiation antigen. While the binding of 125I-insulin-like growth factor I (IGF-I) remained relatively constant during differentiation, binding of 125I-IGF-II increased 2-3-fold. F...

Resistin (Rstn) is known as an adipocyte-specific secretory factor that can cause insulin resistance and decrease adipocyte differentiation. Conversely, based on various studies, insulin-like growth factors (IGFs) can improve insulin resistance and stimulate adipocyte adipogenesis. Whether IGFs exert their effects through the control of Rstn's production or modulation of Rstn's action is unknow...

The body growth of animals is regulated by growth hormone and IGF-I. The classical theory of this regulation is that most IGF-I in the blood originates in the liver and that body growth is controlled by the concentration of IGF-I in the blood. We have abolished IGF-I production in the livers of mice by using the Cre/loxP recombination system. These mice demonstrated complete inactivation of the...

BACKGROUND/AIMS Physiological growth hormone (GH) secretion and insulin-like growth factor-I (IGF-I) levels are greater in young compared to older adults. We evaluated IGF-I levels and predictors of IGF-I responses in young adults on GH replacement. DESIGN From the KIMS database, 310 young adults (age 15-26 years) with severe GH deficiency related to childhood-onset disease and commenced on '...