Abstract
Summary
It was shown that lymphocytes and lymphocyte products stimulated hyalu-ronic acid (HA) synthesis in cultures of human retrobulbar fibroblasts. This stimulation was simulated by dibutyryl cyclic AMP (DbcAMP), 2 × 10-4-10-2 M, and potentiated by theophylline, 10-4 M. Lymphocytes induced a significant increase in the cAMP concentration within the fibroblasts. These data support the concept that the lymphocyte stimulation of HA synthesis is mediated by cAMP.
However, lymphocytes induced greater glucose utilization by the cultures than DbcAMP. Also, the intrinsic viscosity of the HA was decreased by lymphocytes but increased by DbcAMP. Lymphocytes probably produce more effects in the fibroblasts than those mediated by cAMP.
Hydrocortisone inhibited both the cAMP and the HA responses to lymphocytes but potentiated the stimulation of HA synthesis by DbcAMP. Hydrocortisone thus appears to interfere with the earliest effects of lymphocytes, possibly inhibiting the binding of the active factor in lymphocytes to retrobul-bar fibroblasts.
Dr. C. W. Castor provided valuable advice in the preparation of this manuscript. Expert technical assistance provided by Piyush Kothary, Deborah Weiker, and Howard Kirchick was greatly appreciated. The author is also pleased to acknowledge the expert editorial assistance of Cornelia Osborn.
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