## Abstract PG19 mouse melanoma cells arrest growth when they become confluent in medium containing low concentrations of serum. Under these conditions, insulin does not stimulate DNA synthesis in the mouse melanoma cells, whereas it does in mouse embryo fibroblats and fibroblast Γ melanoma hybrids
Responsiveness to insulin is a dominant characteristic in somatic cell hybrids
β Scribed by Daniel S. Straus; Robert A. Williamson
- Publisher
- John Wiley and Sons
- Year
- 1978
- Tongue
- English
- Weight
- 682 KB
- Volume
- 97
- Category
- Article
- ISSN
- 0021-9541
No coin nor oath required. For personal study only.
β¦ Synopsis
Abstract
The mouse melanoma cell line PG19 has been found to be unresponsive to the growthβstimulatory action of insulin, although it responds well to other growth factors present in serum. Insulin stimulates DNA synthesis in mouse embryo fibroblasts, and responsiveness to insulin has been found to be a dominant characteristic in mouse fibroblast x PG19 hybrids. To examine the possibility that the unresponsiveness to insulin of the melanoma cells is attributable to a lack of insulin receptors, we have measured the binding of ^125^Iβlabeled insulin to the fibroblasts, melanoma cells, and fibroblast x melanoma hybrids. Insulin binds to the surface of the melanoma cells; however, the binding affinity appears to be lower than that observed for binding to diploid fibroblasts. In addition, the dissociation of insulin from the melanoma cells is not accelerated by excess unbound insulin, a kinetic effect observed in the dissociation of insulin from the fibroblasts and fibroblast x melanoma hybrids. This suggests that the class of insulin receptors characterized by this effect is absent on the PG19 cells, and present on the fibroblasts and fibroblast x PG19 hybrids.
π SIMILAR VOLUMES
A commonly occurring sequence variant in the islet-specific promoter of the glucokinase gene (-30 G to A) has been variably reported to be associated with reduced insulin secretory responses to oral glucose. The effect of this promoter variant may be subtle and only become apparent under conditions