The effect of feed (energy/protein) restriction on circulating concentrations of @entity70118 , and IGF-binding proteins (IGFBPs) was examined in young (4-week-old) @entity1573 . Increasing levels of feed restriction caused progressive @entity851 , as evidenced by decreased body-weight gain and reduced bone growth. Plasma concentrations of both @entity2090 and @entity20019 were decreased, and the degree of reduction in the plasma concentrations of these growth factors appeared to be related to the magnitude of feed restriction. A tendency for greater decreases in these growth factors appeared to be associated with greater feed restriction at the majority of time points evaluated. However, nutritional restriction had a greater effect on plasma concentrations of @entity2090 than on those of @entity20019 . The reductions in plasma concentrations of @entity2090 were observed earlier in the experiment and at a lower degree of nutritional deprivation than for plasma concentrations of @entity20019 , possibly suggesting greater sensitivity of @entity2090 plasma concentrations to feed restriction. Three IGFBPs with molecular weights of 30, 36, and 40 kDa were detected by radioligand assay following separation by @entity214 -electrophoresis. The 30-kDa IGFBP was most affected by feed restriction with binding activity of this IGFBP increased by 2 days of feed restriction irrespective of the degree of feed deprivation. The binding activity of the 36-kDa IGFBP was increased, albeit transiently, on the second day of feed restriction. Nutritional restriction had no discernible effect on the binding activity of the 40-kDa IGFBP. Increases in the binding activity of the 30-kDa IGFBP appeared to correspond with the observed decreases in @entity2090 plasma concentrations. This suggests decreased bioavailability of @entity2090 , and possibly @entity20019 , attributed to the formation of a complex between @entity2090 and the 30-kDa IGFBP during feed restriction. The initial increase in binding activity of the 36-kDa IGFBP may suggest that this binding protein also plays a role in the regulation and availability of circulating concentrations of @entity2090 and @entity20019 . Although the binding activity of the 40-kDa IGFBP was unaffected by feed restriction, we can not exclude its importance in the regulation of @entity2090 . The substantial binding activity of the 40-kDa IGFBP observed in this experiment suggests that it is one of the major @entity1573 IGFBPs, and that its role in @entity2090 regulation warrants further study.

The effects of dietary restriction on XXXX , and IGF-binding proteins in @entity1573 .

@entity851 :: ('MESH:D006130', 'Disease') :: ['growth retardation'] @entity20019 :: ('100327807(Tax:9031)', 'Gene') :: ['IGF-II'] @entity1573 :: ('9031', 'Species') :: ['chickens', 'chicken'] @entity70118 :: ('395097;100327329;100327807', 'Gene') :: ['insulin-like growth factor (IGF)-I and II'] @entity2090 :: ('100327329(Tax:9031)', 'Gene') :: ['IGF-I'] @entity214 :: ('CHEBI:8984', 'Chemical') :: ['SDS']
@entity70118 :: (395097;100327329;100327807,Gene) :: ['insulin-like growth factor (IGF)-I and II']
