[Significance and detection of insulin-like growth factor I in vitreous with proliferative retinal diseases by radioimmunoassay].

The insulin-like growth factor I (IGF-I) levels in 67 vitreous samples taken from 57 patients with various proliferative retinal diseases and 10 normal subjects were detected by radioimmunoassay (RIA). The acid-ethanol-extracted (AEE) method was used to remove the IFG-binding protein before the detection. Our results revealed that IGF-I levels were increased to varying extents in these patients' vitreous. The IGF-I levels in the vitreous with proliferative diabetic retinopathy (PDR) and central retinal vein occlusion (CRVO) were significantly higher than those of the controls. In the PDR group, the increased IGF-I level in the vitreous was positively correlated with the level in serum. The increased IGF-I level in vitreous may play an important role in the development and pathogenesis of proliferative retinal diseases. Great differences were found between the native and the AEE treated vitreous, suggesting that the binding protein posed an obvious interference on the detection of IGF-I by RIA.