Effects of hypothyroidism and hyperthyroidism on serum glycoproteins in experimental rats

Hypothyroidism and hyperthyroidism were induced in adult female Sprague Dawley rats by feeding 0.05% propylthiouracil and 0.0012% L-thyroxine in drinking water. Contents of protein-bound hexose, fucose, hexosamine and sialic acid in serum were estimated in experimental rats. The results showed an increase in the protein bound hexose, fucose, hexosamine and sialic acid levels in hypothyroid rats and decrease in hyperthyroid rats. The increased content of serum glycoproteins in hypothyroid rats might possibly have come from disruptions of membranes. Depleted glycoproteins in hyperthyroid animals might be due to increase in depolymerisations of glycoproteins and accelerated secretion of glycoproteins with urine.