The Glycoproteins and Fluidity of Multinodular Goiter Euthyroid Plasma Membranes

Abstract

Changes in membrane composition and fluidity may reflect derangements in cellular functions. In plasma membranes (p.m.’s) they can modulate adenylate cyclase activity [1, 2]. Differences in both composition and physicochemical state could be demonstrated when comparing thyroid p.m.’s obtained (method as in [3]) from patients with normal thyroid and patients with multinodular goiter euthyroid gland. Normal thyroid membranes displayed higher protein-to-phospholipid ratios and a lower 5’-nucleotidase specific activity (expts. in triplicate on 1 goiter and 2 normal thyroid p.m. preparations; ±S.E.M.’s):

• protein:phospholipid (w/w): normal, 8.59 ±0.41; goiter, 4.26 ±0.15;

• cholesterol:phospholipid (molar ratio basis): normal, 0.69 ±0.08; goiter, 0.38 ±0.03;

• 5’-nucleotidase (nmol/min/mg protein): normal, 8.3; goiter, 18.4.

An Addendum outlines lectin specificities (at Editors’ suggestion).