Journal of Clinical Endocrinology & Metabolism, Vol 61, 252-257, Copyright © 1985 by Endocrine Society

ARTICLES

The effect of glucose deprivation or 2-deoxy-D-glucose on the monodeiodination of thyroxine in human fibroblasts in culture

S Ishikawa, T Saito and T Kuzuya

The effect of glucose deprivation or 2-deoxy-D-glucose on monodeiodination of T4 to T3 and rT3 was examined in human skin fibroblasts in culture. When the cultured cells were exposed to glucose- free medium containing 1 X 10(-7) M T4 for 48 h, the cellular T4 level was similar to that of cells incubated in medium containing 1 mg/ml glucose. The intracellular T3 level significantly decreased and, in contrast, the intracellular rT3 level markedly increased compared to those levels in control cells. The intracellular T3 to T4 ratio was significantly lower, while the intracellular rT3 to T4 and rT3 to T3 ratios were significantly higher in cells exposed to glucose-free medium than in control cells. Similar results were obtained with 2- deoxy-D-glucose. Exposure of the cells to medium containing varying concentrations of 2-deoxy-D-glucose and 2 X 10(-7) M T4 for 24 h significantly reduced cellular accumulation of T4 compared with that in the control medium. The cellular rT3 to T4 and rT3 to T3 ratios were significantly greater in the cells incubated in medium with increasing concentrations of 2-deoxy-D-glucose. However, the cellular T3 to T4 ratio did not decrease in the test groups. These results, therefore, indicate that either glucose deprivation or the presence of 2-deoxy-D- glucose markedly altered the monodeiodination of T4 in cultured human fibroblasts, i.e. they caused a decrease in T3 production and, conversely, an increase in rT3 production by the cells.