Vit. B12 in Thyrotoxicosis and Myxedema.

Abstract
Summary The whole-blood B12 values in 10 hyperthyroid subjects before and after a load dose of B12 were lower than for a normal and a myxedematous group. The mean 8-hour urinary excretion after B12 administration in hyperthyroid subjects was considerably lower than in the normal and myxedematous groups. These data suggest that B12 turnover and demand is appreciably greater in hyperthyroidism and appreciably lower in myxedema.