14 Urinary Acid Mucopolysaccharides in Myxedema

Abstract

Changes of the skin in myxedema are thought due to changes in its composition of acid mucopolysaccharides (AMPS). In the skin of the hypothyroid rat it has been shown that the content of hyaluronic acid is increased and the content of chondroitin sulfate decreased. A study of the changes in the urinary excretion of acid mucopolysaccharides in two children with acquired myxedema was carried out in order to gain more knowledge about the character of myxedema in humans. Twenty-four hour urines were collected on both children before and at the beginning of treatment with dessicated thyroid. AMPS were precipitated with cetyl trimethyl ammonium bromide and excretion expressed as mg of hexuronic acid/gm of creatinine. AMPS were then fractionated on columns of Dowex 1X2 (Cl-) and eluted with 6 stepwise gradients of NaCl. Components in each fraction were identified by microelectrophoresis on cellulose acetate, analysis of hexuronic acid, hexosamine and sulfate content and identification of the specific hexosamine by paper chromatography. Pretreatment total AMPS were normal for both children and remained so during initial treatment with dessicated thyroid. However, chromatographic fractionation of the pretreatment urinary AMPS yielded a product in the first fraction which is nearly identical in both children and which appears to be hyaluronic acid. Hyaluronic acid is not found in this fraction of AMPS from control urine in this laboratory. The results suggest that human myxedema also contains increased hyaluronic acid. (SPR)