Interactions between growth hormone, insulin-like growth factor I, and basic fibroblast growth factor in melanocyte growth.
The study indicates that growth hormone and insulin-like growth factor I can stimulate melanocyte growth in vitro, but clinical implications remain unclear.
Where it sits
this study against the rest of the igf-1 des (des(1-3) igf-1) corpusSummary and findings
The study examined the role of growth hormone (GH) and insulin-like growth factor I (IGF-I), including des(1-3)IGF-I, in melanocyte growth in vitro. It was found that GH stimulates melanocyte growth when combined with IGF-I or des(1-3)IGF-I. The study also noted that IGF-I is more effective than des(1-3)IGF-I at low concentrations.
Abstract
Melanocytes, highly differentiated neural crest-derived cells, are located in the basal layer of the epidermis, where they play a role in protecting against UV damage in the skin. Previous studies suggest that both growth hormone (GH) and the insulin-like growth factor I (GH/IGF-I) system may be important for melanocyte growth and function. We have therefore characterized the role of the GH/IGF system in melanocyte growth in vitro and its interaction with the local growth factor basic fibroblast growth factor (bFGF). Analysis of the effects of GH, IGF-I, and bFGF and combinations of these growth factors on melanocyte growth in vitro revealed that 1) GH stimulates the growth of melanocytes when combined with IGF-I, des(1-3)IGF-I [an analog of IGF-I that has a reduced binding affinity for IGF-binding proteins (IGFBPs)], or bFGF, either separately or in combination; 2) in contrast to the lack of effect of GH or bFGF alone, both IGF-I and des(1-3)IGF-I enhance melanocyte growth in a dose-dependent manner; and 3) IGF-I is more efficacious in eliciting a growth response at low concentrations compared to des(1-3)IGF-I. Using Western ligand blotting, affinity cross-linking, immunoprecipitation, RIA, and Northern analysis, we show that cultured human melanocytes synthesize and secrete minimal amounts of IGFBP. IGFBP-4 is the major IGFBP produced by these cells when cultured in complete growth medium or in the presence of either IGF-I or des(1-3)IGF-I alone. In conclusion, these studies provide support for a role for both GH and IGF-I in the growth of human melanocytes in vitro, involving synergy with bFGF. Low levels of melanocyte-derived IGFBP-4 may play a role in enhancing the modulation of IGF action.
Background
Not reported in abstract.
Methods
Not reported in abstract.
Results
Not reported in abstract.
Interpretation
Not reported in abstract.
Limitations
Not reported in abstract.