RECEPTOR-MEDIATED INDUCTION OF HUMAN GLOMERULAR EPITHELIAL-CELL ALKALINE PHOSPHODIESTERASE-I BY GLUCOCORTICOIDS

Alkaline phosphodiesterase I was demonstrated in human glomerular mesa ngial cells (HGEC) as an ectoenzyme. Treatment of HGEC by dexamethason e increased surface phosphodiesterase I activity in a dose- and time-d ependent manner. Maximal increase of phosphodiesterase I activity, abo ut twice, occured after treatment with 5 mu M dexamethasone for 6 days . Cycloheximide prevented and RU 38486, a glucocorticoid receptor anta gonist, suppressed the dexamethasone induced increase in phosphodieste rase I activity. This study shows that HGEC have a surface phosphodies terase I controlled by glucocorticoids through a receptor-mediated mec hanism.