Inhibition of Glycosaminoglycans Production in Retrohulbar Fibroblast Cultures by Ethacrynic Acid and Hydrocortisone

Lymphocytes stimulated the production of glycosaminoglycans (GAG) by cultures of human retrobulbar fibroblasts, and this interaction is proposed as an in vitro analogy to Graves' ophthalmopathy. Ethacrynic acid (EA), 10–25 μg/ml, caused a significant reduction in the basal synthesis of GAG by the fibroblasts. The effects of EA on lymphocyte stimulated fibroblasts were primarily related to lowering the basal rate of GAG production and little, if any, to the stimulation process. Neither chlorothiazide, 50–500 μg/ml, nor furosemide, 5–25 μg/ml, had appreciable activity in the cultures. Hydrocortisone, 1 μg/ml, inhibited the lymphocyte lymphocyte stimulated GAG but only slightly lowered the basal GAG levels. The effects of EA and hydrocortisone were additive, but the combination did not completely abolish the enhancement of GAG concentrations induced by lymphocytes. Glucose utilization by unstimulated fibroblasts was increased by EA, but this change could not be detected in the stimulated cultures where lymphocytes were responsible for the accelerated glucose metabolism. The concentrations of EA necessary to affect the cultures were close to those which brought about toxic changes.