Effect of total food deprivation on the proteoglycans of rat hyaline cartilage and bone.
Existing hypotheses suggest that the effect of food deprivation on bone occurs via alterations in the synthesis of the organic matrix. Thus, this work was carried out to characterize the modifications of the physico-chemical properties of the proteoglycans (PG) of rat hyaline cartilage and femur. Male Wistar rats were assigned at random to a control group which was fed a standard pellet diet or to an experimental group which was given water "ad libitum" and starved over the experimental period. On day 4 or 8 the animals were administered a dose of 35S, weighed and killed. PG and glycosaminoglycans (GAG) were isolated from femurs and xyphoid cartilages. Uptake of 35S, GAG distribution patterns, PG molecular weight, molecular size of the side chains and the PG density gradient were determined. The aforementioned parameters decreased significantly after 4 and 8 days of total starvation. The GAG distribution pattern only exhibited a reduction of the Chondroitin-4-Sulphate fraction. These changes could alter the binding properties of PG to other macromolecules such as collagen which plays an important role in the ossification process.