ELECTROPHORETIC STUDIES ON THE DISTRIBUTION OF HEXOSAMINE IN PROTEINS OF THE THYROID GLAND

Abstract

Thyroid glands of various species of animals and man have a high concentration of hexosamine (1-2% dry weight). Thyroglobulin is shown to contain most of the hexosamine (72%) as well as thyroid hexoses (61%) but no uronic acid. Thyroglobulin is therefore a glycoprotein, rich in hexosamine (3.3%) and hexose (4.5%). An acid-soluble glycoprotein was also demonstrated in the thyroid gland. It is present in small amounts and is very rich in hexosamine (11.5%). The evidence presented does not support the observations that the thyroid gland (exclusive of connective tissue) contains a mucopolysaccharide. Hypophysectomized rats or rats treated with thyrotropic hormone, despite changes in thyroid weight, develop no changes in total thyroid hexosamine. Stress (fracture) does not influence the total amount or concentration of hexosamine in the thyroid.